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CHEMISTRY FOR NURSES 



A TEXTBOOK OF 

CHEMISTRY FOE NURSES 



BY 

FREDUS N. PETERS, A.M., Ph.D. 

/i 

Author of "Experimental Chemistry," "Laboratory Experiments," "Modern 

Chemistry," etc.; Formerly Professor of Chemistry and Director of 

Laboratories, Kansas City College of Pharmacy; Professor Organic 

Chemistry Hahnemann Medical College. Director of Laboratories 

and Professor of Chemistry and Metallurgy, Kansas City 

Dental College; Head of Science Department, Kansas 

City Central High School. 



ILLUSTRATED 



ST. LOUIS 

C. V. MOSBY COMPANY 

1919 



Q 



Copyright, 1919, By C. V. Mosby Company 



Press of 

C. V. Mosby Company 

St. Louis 



^CU 53 039 7 

JUN I3uid 



PREFACE 

The science of chemistry enters into every phase of 
everyday life. Whether it be on the battle front 
where the chief aim is the wholesale destruction of 
human life, or at the rear in the hospital tent where it 
is the loving duty of the nurse to save life and woo 
back the wasting strength, chemistry is a potent factor. 
No day of our lives, whether we be the humble la- 
borer, or the exalted magistrate who must direct the 
destiny of millions, can be spent without a knowledge 
of chemistry on the part of some one contributing to our 
safety and welfare. This little book has been prepared, 
therefore, with the idea of more fully equipping those 
whose angelic visitations and watchful care must inev- 
itably wield an ever increasing influence upon unfor- 
tunate humanity. 

The book is very simply written so that all may under- 
stand. It begins with the most familiar substances of 
life and leads up to those not so well known. The au- 
thor has aimed at all times to avoid the technical: chem- 
ical theory has been introduced when such would add 
greatly to the understanding of the phenomena at 
hand: at other times it has been omitted. The author 
has aimed at all times to be scientific and truthful. 
The practical phases of chemistry are everywhere re- 
membered and emphasized, especially those that con- 
cern the great mass of humanity. Those substances 
which by their applications become our daily servitors, 
and those which, on the contrary, would threaten and 
endanger life, have been introduced and studied care- 



10 PREFACE 

fully. A variety of tables has been added near the end 
of the book as an appendix. The author feels that these 
will be both valuable and helpful in many ways, as they 
give, in a concise form, information often needed quickly. 
No apology is made for the fact that the text is con- 
siderably larger than most of those offered up to this 
time. The responsibilities of the nurse are so great and 
the opportunities for the alleviation of suffering are so 
abundant that a wide knowledge of the Queen of Sci- 
ences can never come amiss. It is hoped that this book 
may be found a source of real help and inspiration. 

Fredus N. Peters. 

Kansas City, Mo. 



CONTENTS 



CHAPTER I 
Introduction 15 

CHAPTER II 
Water and Its Composition 26 

CHAPTER III 
Hydrogen 38 

CHAPTER IV 
THE ATMOSPHERE 46 

CHAPTER V 
Oxygen 56 

CHAPTER VI 
Ozone and Hydrogen Dioxide 66 

CHAPTER VII 
Common Salt and Sodium 72 

CHAPTER VIII 
Chlorine and the Halogen Family 79 

CHAPTER IX 

Gases and Some Gas Laws . . . • 92 

11 



12 CONTENTS 

CHAPTER X 
Symbols and Formulas 108 

CHAPTER XI 
Oxides, Acids, Bases, and Salts 115 

CHAPTER XII 
Ammonia and Nitric Acid . 125 

CHAPTER XIII 
Valence 136 

CHAPTER XIV 
Carbon and a Few Compounds 141 

CHAPTER XV 
Some Everyday Carbon Compounds 157 

CHAPTER XVI 
Sulphur and Compounds 177 

CHAPTER XVII 
The Nitrogen Family 193 

CHAPTER XVIII 
Silicon and Compounds 206 

CHAPTER XIX 

Sodium Family and Its Compounds 210 

CHAPTER XX 
The Calcium Family 220 






CONTENTS 13 

CHAPTER XXI 
The Magnesium Family 230 

CHAPTER XXII 
The Aluminum Family 239 

CHAPTER XXIII 
The Copper Family 247 

CHAPTER XXIV 
The Lead Family 254 

CHAPTER XXV 
Iron and Compounds 258 

CHAPTER XXVI 
Some Common Poisons 261 

APPENDIX 
Appendix . . 275 

GLOSSARY 
Glossary 288 

BIBLIOGRAPHY 
Bibliography 294 



CHEMISTRY FOR NURSES 



CHAPTER I 

INTRODUCTION 

Outline — 

1. Matter, Old Theories of. 

2. Transmutation of Matter. 

3. False Methods of Reasoning — 

Aristotle, Geber, Paracelsus. 

4. Robert Boyle's theories. 

5. Elements. 

6. Compounds. 

(a) Method of Naming. 

(b) Parts of Compounds. 

(c) Chemical Affinity, What? 

7. Mixtures. 

8. Chemical Union, What? 

9. Chemical Change. 

(a) Additive. 

(b) Simple Decomposition. 

(c) Metathesis or Double Decomposition. 
Exercises for Review. 

1. Some Old Ideas About Matter. — From very early 
times, certain philosophers have regarded earth, air, 
fire, and water as the four fundamental or primary sub- 
stances from which everything we know can be made. 
Not merely did they believe these four the basis of every- 
thing ; but, more than this, they felt sure it was possible 
to change one or more into another. For example, when 

15 



16 CHEMISTRY FOR NURSES 

a vessel of water is heated upon a stove or allowed to 
stand in the sun, the water disappears. "We say it evap- 
orates: they thought that it had been changed by the 
heat into air, or in other words, that heat added to water 
produces air. 

Again, when a tumbler of ice water is left sitting in a 
warm room, in a short time drops of moisture appear 
upon the outside of the glass. We say that the moisture 
in the air has been condensed upon the cold surface; the 
old philosophers thought as heat had converted the 
water into air, so cold had changed the air back into 
water. 

When pure water is evaporated, it leaves no resi- 
due; but impure or hard water under like conditions 
leaves more or less of a sediment upon the walls of 
the containing vessel. This appears as "lime" or 
"scale" upon the inside of the tea kettle in the kitchen, 
or in the hot-water coil in the furnace, or in the boiler of 
the steam engine. We understand what this is ; but the 
ancient philosophers thought that while by heat the 
greater part of water changes into air a small portion 
becomes earth. So according to their reasoning there 
was a very close relation existing among the four pri- 
mary substances, and it was no difficult matter to change 
one into another. 

2. Other Obse'rvations. — The old philosophers had ob- 
served other facts also which led them to believe in the 
transmutation of one substance into another. For ex- 
ample, their picks and other steel tools, left standing for 
a few days in the water which gradually seeped into 
their copper mines, always became coated with a thin 
layer of copper. This may be illustrated by immersing 
a bright nail in a dilute solution of copper sulphate for 
a few minutes. They had no true knowledge of what 



INTRODUCTION IT 

was happening, but believed the iron was being changed 
into copper. They knew also, that by fusing copper with 
a certain mineral, called cadmia, Avhich we now know con- 
tains zinc, they could obtain a substance we call brass, 
which may closely resemble gold. They knew it was not 
gold, but they believed that if they could but discover ex- 
actly the proper proportions to put together they would 
succeed in producing the more valuable metal, as good as 
any from nature's best mine. This change may be fur- 
ther illustrated by putting a few copper cents into a so- 
lution of mercuric nitrate and allowing them to remain 
a few minutes. Upon removing and rubbing them for a 
moment they seem to have become silver. It is not 
strange, therefore, that they should have believed in the 
transmutation of the metals and that the chief aim of 
the chemist of the alchemistic era was the preparation 
of gold from the baser metals. 

3. Old Methods of Reasoning. — Aristotle, born 384 
b. c, one of the greatest of ancient philosophers, once pro- 
claimed that "a globe full of ashes or sand will hold as 
much water as if empty." Such was the manner of 
thought of that day that no one for centuries presumed 
to question the statement. At the present time no sci- 
entist would dare publish anything as fact which he did 
not feel sure was based upon a large number of careful 
and accurate experiments. Any scientific statement now 
as soon as published is subjected by scores of scientists 
to the most rigid tests, so that a few weeks or months at 
the outside demonstrate the truth or falsity of the po- 
sition. Not so in Aristotle's time. The very fact that he 
had stated the proposition was sufficient, and no one 
even thought of making the experiment, simple as it was, 
to determine whether the assertion were true. 

Twelve hundred years later, Geber, the great Arabian 



18 CHEMISTRY FOR NURSES 

chemist whose doctrines were spread throughout Europe 
after the Saracen invasion of Spain, declared that all the 
metals were but different mixtures of mercury and sul- 
phur; that silver and gold were especially rich in mer- 
cury and the baser metals were abounding in sulphur. 
It seems that Geber was somewhat of an experimenter 
and was forced to admit to himself, at least, though he 
never did to the public, that the mercury and sulphur 
as he knew them in the laboratory would not bring about 
such results as his theory maintained; further that the 
mercury and sulphur in the free state were not identical 
with what he described as the same in combination: yet, 
in spite of all this, he never admitted the inaccuracy or 
falsity of his theory. Furthermore, his disciples all over 
Europe, accepted his doctrines with equally unquestion- 
ing faith as had those of Aristotle during all the pre- 
ceding centuries. 

Five hundred years passed away and with them the 
age of alchemy. The first half of the sixteenth century 
introduces a new school of chemists, the physician chem- 
ists, or iatrochemists, as they are generally known. Of 
these, Philippus Aureolus Paracelsus Theophrastus 
Bombastus, or, as he is usually called, Paracelsus, was 
easily the leader. He maintained that "Man is a chem- 
ical compound. His ailments are due to some alteration 
in his composition and can only be cured by the influence 
of other chemical compounds. ' ' His belief that the body 
is composed of mercury, sulphur and salt, it will be 
readily seen, was but a modification of the ideas of Geber. 
An increase of sulphur in certain organs of the body 
caused fever; of mercury, paralysis; of salt, diarrhea 
and dropsy. Too little sulphur resulted in gout ; and so 
on, for all the ills of mankind. With this theory accepted 



INTRODUCTION 19 

as the truth, it was but a short step to the giving of 
calomel for a great variety of ailments, presumably with 
the assumption that the digestive organs with more dis- 
cretion than the mind would send the mercury to those 
organs most in need of it. Here, too, undoubtedly, be- 
gan the use of sulphur so extensively as a medicine, 
which in the practice of Paracelsus met with such won- 
derful results that even the sceptical nineteenth cen- 
tury did not succeed entirely in stopping. 

4. Modern Ideas. — In time, however,, all this passed 
away. Robert Boyle, born in 1626, expressed disbelief 
in the four elements of the ancients as well as in the 
one, to which some held, and declared there were many 
primary substances to which he gave the name of ele- 
ments. Furthermore by his own example he emphasized 
the truth which had been dawning for years upon the 
scientific world that only through experiment can ab- 
solute scientific knowledge be determined. Such was 
his influence that he is often called the "Father of 
Physics and Chemistry." 

With the birth of new ideas as to the composition of 
matter and a disbelief in the transmutation of the met- 
als, medicine and chemistry became separate sciences, 
each imbued with the spirit of making sure by experi- 
ment of any position taken. Today, medicine no less 
than chemistry permits of no dogmatic theory as to 
disease. If a new scourge appears as did yellow fever 
some years ago, numbers of young physicians are ready 
to offer their lives, if need be, to learn the true cause ; 
the x-ray reveals to the surgeon the exact condition of 
the broken bone or the location of the bullet for which 
he must search; it shows the ulceration at the base of 
the tooth or other abnormal conditions and renders sure 
the operation. In the laboratory culture the microscope 



20 CHEMISTRY FOR NURSES 

shows the tubercle bacilli or the diphtheria germ as 
well as various others. So, in countless ways the mod- 
ern physician makes sure of his diagnoses, after 
which proper treatment is comparatively simple. 

5. What is an Element? — An element in the sense in 
which Boyle used the term and as used at the present 
time is a substance which consists of a single kind of 
matter, hence is not capable of being reduced to any- 
thing simpler. There are now known a few more than 
eighty of these simple substances, but it is possible that 
some of the rarer of them may not be really elements. 
It is probable also that others may be added to those al- 
ready known. Some of the commoner ones are the met- 
als, gold, silver, lead, mercury, aluminum, etc. and ox- 
ygen, nitrogen, hydrogen, carbon, sulphur and chlorine. 

6. Compounds. — A compound is a substance contain- 
ing two or more elements chemically united, always in 
exactly the same proportion by weight. For example, 
water is a compound, consisting of eight parts of ox- 
ygen and one part of hydrogen, from which proportions 
it never varies. 

Compounds, How Named. — Chemists have agreed 
upon and rigidly adhere to a plan of naming compounds 
in such a way as to indicate the composition as nearly 
as possible. Thus mercuric oxide is a compound which 
contains only mercury and oxygen; any compound 
whose name ends in ide contains only the elements 
named, and with the exception of hydroxides, contains 
only two elements. Thus, potassium chloride contains 
potassium and chlorine; magnesium bromide, mag- 
nesium and bromine; while sodium hydroxide contains 
sodium, hydrogen and oxygen. If the name of a com- 
pound ends in ate the fact is indicated that it contains 
oxvgen in addition to the two other elements mentioned. 



INTRODUCTION 21 

Thus, potassium chlorate contains potassium, chlorine 
and oxygen: copper sulphate, copper, sulphur and ox- 
ygen. 

Parts of a Compound. — It is well known that a mag- 
netic needle, suspended by a thread or upon a pivot, 
always points approximately north and south. AYe 
often speak of the two ends of the magnet as the pos- 
itive pole and the negative pole. In an electric circuit, 
the electrode where the current enters is called the 
anode, or positive electrode, and the one where it exits, 
the cathode, or negative electrode. Of course the terms, 
positive and negative have no real meaning and are 
used merely for convenience in referring to certain por- 
tions of the circuit. Anode and cathode mean, respec- 
tively, the path or road in and the road out. Further- 
more, it is well known that the positive pole of a magnet 
always repels the positive pole of another magnet, but 
attracts the negative pole: from this fact is derived the 
law stated in physics that "Like poles repel, and unlike 
poles attract." 

Generally speaking, the eighty elements mentioned 
above may be roughly divided into two groups, positive 
and negative. This fact grows out of the law stated just 
above and shown by the following experiment. If a so- 
lution of common salt, sodium chloride, is subjected to 
the passage of an electric current, the sodium always 
goes to the negative electrode and the chlorine to the 
positive: likewise in a solution of potassium bromide, 
the potassium will be found collecting at the negative 
electrode and the bromine at the other. Experiments 
upon compounds of all the elements show like results, 
hence the statement at the beginning of this paragraph. 
In the main the so-called metals are positive and the 



22 CHEMISTRY FOR NURSES 

nonmetals are negative. Furthermore, in the study of 
compounds we find that as a general rule they all con- 
sist of a positive and a negative element, or group, 
united with each other. Thus, sodium chloride con- 
tains sodium, positive, and chlorine, negative ; potassium 
sulphate, positive potassium, and negative, the group 
sulphur and oxygen, which will be more fully explained 
later. It would seem, therefore, that the force which 
holds elements together in a compound is electrical in 
nature. In fact, the expression "chemical affinity" used 
so often in times past has no real meaning and is seldom 
used now. One more thing should be observed by the 
student and that is that in writing or reading the name 
of a compound the positive part is always given first as 
a general rule. Thus, chromium nitrate may be a com- 
pound entirely unknown to the student, yet from the 
fact just stated, he may know that chromium is the 
positive element in the compound and the negative por- 
tion is the group containing nitrogen and oxygen. 

7. Mixtures. — Mixtures are different from compounds 
in that the two or more substances of which they are 
composed are not chemically united and are not neces- 
sarily in any fixed or definite proportion. Thus, brass 
is a mixture of zinc and copper in greatly varying pro- 
portions. It may contain 65 per cent of zinc and 35 
per cent of copper or it may run as low as 5 per cent of 
zinc and the remainder of copper, with variations all 
the way between these limits, according to the purpose 
in view. The air, likewise, is a mixture, mainly of five 
substances; two of them, nitrogen and oxygen, are al- 
ways nearly in the same proportion, so nearly in fact, 
that for many years they were regarded as being com- 
bined, but later more accurate measurements showed 
that even these two vary at different times and places 
Further, in another chapter it will be shown that there 



INTRODUCTION . 23 

are excellent reasons for assuming that they are not 
chemically united. 

8. What is Chemical Union? — The expression "chem- 
ically united" has been used several times in the pre- 
ceding paragraph. By it is meant that two or more 
elements in uniting chemically form a new substance, 
having properties essentially different from those of 
the original elements, while they lose their individual 
identities. Thus, water was said to consist of hydrogen 
and oxygen: at ordinary temperatures these are both 
gases, one very highly inflammable, the other necessary 
for all ordinary combustion. When chemically united, 
the resulting product is a liquid at ordinary tem- 
peratures, not combustible like the hydrogen, not an 
aid to combustion like oxygen. In uniting chemically 
the two elements have lost their individual character- 
istics and have formed a substance altogether different 
from either. To illustrate again, sodium is a silvery 
white metal, lighter than water which it decomposes 
rapidly and which in the mouth or upon the wet hand 
would readily catch fire and produce most serious 
chemical burns. Chlorine is a heavy, yellow, corrosive 
gas, used in the World War as a terribly destructive 
agent: combine these two poisonous elements and we 
have common salt, used daily in our food and in mod- 
erate amounts perfectly harmless. In combining, each 
element has lost its destructive properties and formed 
a substance of the greatest commercial value. 

9. Chemical Change'. — A chemical change is one in 
which the substances used, one or more, are destroyed 
as such; new substances are formed with entirely 
different properties. Chemical union, explained in 
the preceding paragraph, is but one kind of chemical 
change. Such as those mentioned, the union of hy- 
drogen and oxygen to form water or of sodium and 



24 CHEMISTRY FOR NURSES 

chlorine to form salt, are called additive reactions; that 
is, the two or more substances have simply been com- 
bined to form one new substance. An experiment eas- 
ily made to illustrate this kind of chemical change is 
that of burning a feAV inches of magnesium ribbon. 
The steel gray metal rapidly combines with the oxygen 
of the air and produces magnesium oxide, commonly 
known as magnesia. 

A second kind of chemical change is called simple de- 
composition which is just the reverse of an additive re- 
action. A single substance by heat or some other force 
is decomposed forming usually two simpler substances 
When a current of electricity is passed through water, 
it is decomposed into its constituents, hydrogen and ox- 
ygen. Again, if a small quantity of mercuric oxide is 
heated in a test tube, in a short time mercury will be 
seen gathering upon the sides of the test tube while the 
presence of oxygen at the mouth of the tube may 
be shown by its causing a glowing pine splinter held 
just above to burst into a flame. 

A third kind of chemical change is known as metath- 
esis, or double decomposition. It is the mutual decom- 
position of two reacting substances, resulting in the 
formation of two entirely new substances. For exam- 
ple, if a small quantity, say about a gram each, of 
mercuric chloride and of potassium iodide be rubbed 
together in a mortar, almost immediately the white mix- 
ture begins to turn pink and increases in color as the 
rubbing proceeds. The very fact that two white com- 
pounds put together produce a red one indicates some- 
thing more than mere mixing has occurred. No two 
white paints could be mixed together to produce a red 
pigment. What really has happened is this: the two 
metals, potassium and mercury, being of positive char- 
acter, as suggested in a preceding paragraph, have 



INTRODUCTION 25 

exchanged places with each other forming two new 
compounds, mercuric iodide and potassium chloride, one 
of which is a brilliant red. 

In the study of chemistry we are dealing much of 
the time with chemical changes most of which will fall 
under one of the three kinds just mentioned. Some 
will be of a mixed character, partaking of the nature 
of two of the kinds mentioned. 

Exercises for Review 

1. Name the four substances regarded by ancient philosophers 
as primary. 

2. Give some evidence they offered for such belief. Why did 
they assume one of these could be transformed into another? 

3. What led them to believe the metals could be transmuted? 
What is meant by transmutation of metals? 

4. What was the method of scientific reasoning in Aristotle's 
day? Illustrate. Who was Geber? What was one of his theo- 
ries? 

5. Who was Paracelsus? What was his idea about the human 
body? Of disease? 

6. "Who was the father of physics and chemistry? What was 
his idea about matter? 

7. What is an element? How many are there? 

8. W T hat is a compound? Name two. 

9. How may you know from the name the composition of a com- 
pound? Illustrate. 

10. What is a magnet? Pole of a magnet? 

11. What is meant by anode? Cathode? 

12. Into what two groups may the elements be divided? 
Why so divided? 

13. What force apparently holds elements together in a com- 
pound? What is chemical affinity? 

14. How is a mixture different from a compound?' Illustrate. 

15. What is meant by chemical union? Illustrate. 

16. What is a chemical change? 

17. Name three kinds of chemical change. Give some ex- 
periment to illustrate each. 

18. Define each kind of chemical change. 



CHAPTER II 

WATER AND ITS COMPOSITION 

Outline — 

1. Water, Abundance, Various Forms. 

2. Water in Food Products. 

3. Composition of Water — Proof. 

(a) By Electrolysis — Volumetric. 

(b) By Synthesis — Gravimetric. 

4. Deliquescence. 

(a) Definition and Illustration. 

(b) Hygroscopic substances. 

5. Water of Combination — Hydrates. 

6. Efflorescence. 

7. Solvent Powers' of Water. 

(a) Hard Waters. 

(b) Water Supplies. 

8. Nature's Method of Purification. 

9. City Water Systems. 

(a) Sewage in. 

(b) Methods of Treatment. 

(c) Treatment for Algae. 

10. Tests for Water. 
Exercises for Eeview. 

1. Abundance. — Water in its various forms is so fa- 
miliar to every one that little need be said of its abun- 
dance. As a liquid and in a partially condensed form 
of steam, fog, and cloud it is known to all; while as 
ice and snow, glaciers and icebergs, it is known only 
in middle and northern latitudes. 

2. Water in Food Products. — Practically all our foods 
contain a greater or less amount of water. Even flour, 

26 



WATER AND ITS COMPOSITION 27 

which might be thought of as entirely free from water 
contains a very considerable amount, averaging in dif- 
ferent samples about ten or eleven per cent. 

Table 

Per cent 

Beans, dry 12.60 

Beans, string, 89.00 

Bread, yeast 36.12 to 37.70 

Cabbage 91.50 

Carrots 88.20 

Cauliflower 92.30 

Celery 94.50 

Cheese 31.38 to 38.60 

Corn 13.12 

Eggs 73.67 

Flour, wheat 10.11 

Meat, lean beef 67.00 to 70.00 

Meat, lean pork 60.00 

Meat, veal 73.30 

Mutton 50.20 

Oat Meal 12.37 

Peas, dry 12.62 

Peas, green 79.93 

Potatoes, sweet 75.00 

Potatoes, white 66.10 to 80.60 

Eice . 13.11 

Turnips 89.60 

Watermelons 92.40 

Likewise, all fresh fruits run high in water, their 
chief food value being in the sugar they contain, in 
addition to the organic acids probably of special value 
in their effects upon the digestive system. Naturally, 
therefore, the human body itself is largely water, it 
being estimated that in the case of a man weighing 150 
pounds the amount of solid matter would be about sixty 
pounds. 



28 



CHEMISTRY FOR NURSES 



3. Composition of Water. — As already stated, water 
was regarded by the ancient philosophers as one of the 
primary substances; but we know now that it is a 
compound, consisting, by volume, of hydrogen, two 
thirds, and oxygen, one third. Proof of this is usually 
made by means of what is known as the Hoffmann ap- 
paratus, shown in Fig. 1. A and K are two platinum 
strips serving as the electrodes and connecting with 
the electric circuit by means of wires enclosed in glass 
tubes passed through the corks C,C, which close the 



Fig 1. — Electrolysis apparatus. 






apparatus at the bottom. S,S are stopcocks by means 
of which the gases may be drawn off at the close of the 
experiment and tested. B is a reservoir to receive the 
excess of water from the electrolytic tubes, B,B. In 
making the experiment, water slightly acidulated with 
sulphuric acid is poured into the central tube, or res- 
ervoir, and the stopcocks opened to allow the water to 
just barely fill the tubes, B,B, up to the stopcocks. A 
suitable, direct current is then switched on and allowed 
to flow until a sufficient amount of gas has collected 









WATER AND ITS COMPOSITION 29 

for testing. Readings taken on the graduated tubes 
at any time show twice as much gas in one as the other. 
To prove that the gases are hydrogen and oxygen the 
following tests may be made which it will be found 
later are the usual ones. Over the tip of the tube con- 
taining the lesser amount of gas, hold a pine splinter 
with a spark upon the end of it; open the stopcock 
cautiously and allow the gas to flow out upon the spark: 
it immediately bursts into a flame. This may be re- 
peated several times, until the gas is exhausted. To 
test the other tube, with a match or small candle, which 
is better, light the gas which flows out upon opening 
the stopcock ; it will burn with an almost invisible flame, 
which is characteristic of hydrogen. 

It will be found that in the electrolysis of water as 
outlined above the hydrogen always goes to the cathode 
and the oxygen to the anode. The reason for this is 
plain when we remember what was said about every 
compound in the preceding chapter, that is, that it 
consists of a positive and a negative element or group. 
Hydrogen belongs to the positive elements and oxygen 
to the negative, hence obeying the law previously stated 
they would be attracted, the former to the negative 
electrode and the latter to the positive. 

Composition by Weight. — By the electrolysis of water 
as just given we learn its composition by volume. It 
is even more important to know what it is by weight. 
This may be readily determined by a simple experiment 
as follows: 

In Fig. 2, K is a generator for the preparation of 
hydrogen; W is a wash bottle containing sulphuric 
acid for the purpose of thoroughly drying the hydro- 
gen ; T is a combustion tube made of hard glass contain- 
ing copper oxide, preferably in what is known as "wire 



30 



CHEMISTRY FOR NURSES 



form ; ' ' TJ is a U-tube containing calcium chloride, a sub- 
stance which rapidly absorbs water ; B is a Bunsen 
burner or some other source of heat. Before beginning 
the experiment several grams of copper oxide are placed 
in the combustion tube and both together weighed ; next 
the calcium chloride tube is nearly filled and weighed. 
Heat is then applied and the current of hydrogen turned 
on, slow at first. Soon the black oxide will be noticed 
turning red like bright copper and this will continue 
till the whole mass has thus changed. At the' same time 




Fig. 2. — Synthesis of water. 

water will be noticed collecting in the U-tube. At this 
stage the heat is removed but the gas is allowed to con- 
tinue till the copper oxide tube has become nearly cool. 
The apparatus is then disconnected and second weigh- 
ings made. The following weights may be taken as 
representing a typical case. 



Copper oxide tube, before heating 35.29 grams 

after heating 28.81 < ' 

Loss, which is oxygen 6.48 ' ' 

Calcium chloride tube, before heating 27.34 grams 

after heating 34.63 ' < 

Gain, which is water 7.29 tl 



WATER AND ITS COMPOSITION 31 

Subtracting the weight of the oxygen from that of 
the water leaves 0.81 grams, which is the weight of the 
hydrogen used in forming the water. It will be ob- 
served that this weight is one eighth that of the oxy- 
gen or one ninth that of the water formed. Owing to 
experimental errors the results are not usually exact, 
but the average of a very large number of experiments 
more carefully carried out than can be done in the or- 
dinary class room shows conclusively that the above con- 
clusions are correct. 

4. Deliquescence. — Deliquescence is the property some 
substances possess of absorbing water from the air when 
exposed and of becoming liquid. Nearly everything ab- 
sorbs some moisture when exposed to the air, but a few 
substances do this to a remarkable degree as indicated 
in the definition of deliquescence just given. Literally 
translated the word means "becoming liquid." An 
excellent example of such compounds is seen in calcium 
chloride used in the experiment outlined in the preced- 
ing paragraph. Other well-known deliquescent com- 
pounds are caustic soda and potash and phosphorous 
pentoxide. A hygroscopic substance is one that will 
become damp upon exposure to the air, but will not 
absorb sufficient water to become a liquid. Most sam- 
ples of table salt become damp in wet weather due, 
however, to the presence of an impurity in the salt 
rather than to the salt itself being hygroscopic. 

5. Water of Combination — Hydrates. — Many chemical 
compounds occur in regular geometric shapes which are 
called crystals, such as cubes, octahedrons, rhombohe- 
drons, etc. These crystals are more often obtained by 
making a solution of the substance in water and evap- 
orating. In such cases it is often true that a very con- 



32 CHEMISTRY FOR NURSES 

siderable portion of the water, instead of passing off 
into the air, goes into combination with the solid. Wa- 
ter thus taken up is called water of combination or often, 
though less properly, water of crystallization. This wa- 
ter is not simply mixed with the solid: if it were, it 
might be removed by pressure or absorption by a piece 
of blotting paper. On the other hand, it is far from a 
stable chemical union, for usually comparatively little 
heat will more or less completely remove it. That there 
is real chemical union, however, is known from the 
fact that when the water is removed the properties of 
the substance are often materially changed. Such sub- 
stances as these are now called hydrates. Some good 
examples of crystalline hydrates are blue vitriol, alum, 
green vitriol, sal soda, borax and many other familiar 
compounds. 

To illustrate how removing the water from such a 
compound changes its characteristics, put a few small 
crystals of blue vitriol into a test tube and cautiously 
heat it in the Bunsen burner. Water will be seen col- 
lecting upon the upper, cooler portions of the tube and 
the copper sulphate itself will lose its crystalline struc- 
ture and at the same time its blue color. When all the 
color has disappeared, allow the tube to cool and add 
a few drops of water. The blue color is instantly re- 
stored and upon evaporating the excess, the crystals 
will again form. It must be believed therefore, from 
the fact that adding water, itself colorless, to a com- 
pound also colorless (white) gives a blue compound, 
that some chemical action has taken place to produce 
so remarkable a change. It will be found if other hy- 
drates are thus tested that they invariably lose their 
crystalline structure when the water is expelled and if 
they are colored, they lose their color also. 



WATER AND ITS COMPOSITION 33 

In referring to these crystalline compounds it is often 
not necessary to use any expression indicating that 
they contain water; but when such is desired it is cus- 
tomary to use the word crystallized or some other ex- 
pression. Thus, we would say crystallized copper sul- 
phate; or, if the compound without the water was in- 
tended, we say anhydrous copper sulphate or whatever 
the compound may be. The term anhydrous means with 
water removed. 

6. Efflorescence. — As stated in the preceding section, 
water of combination may be removed more or less read- 
ily by application of heat. In many cases the tempera- 
ture of an ordinary room is sufficient to cause the loss 
of the combined water. Such substances are said to be 
efflorescent. The word means, literally, becoming flour 
or a powder and is thus used because when loss of the 
water occurs the crystals crumble to a powder. Efflor- 
escence, then, would be defined as the property which 
many hydrates possess of giving up their water of com- 
bination on exposure to the air and becoming a powder. 
An excellent example of such compounds is common 
washing soda or sal soda ; also ferrous sulphate, and 
blue vitriol to a considerable extent, 

7. Solvent Powers of Water. — Water is a nearly uni- 
versal solvent. Practically every mineral in time will 
dissolve to a greater or less extent in water. As a re- 
sult all spring water is more or less "hard" as it has 
dissolved portions of the rocks through which it has 
passed. The virtue of water in therapeutics, applied 
in the case of certain fevers and some other diseases, 
probably lies in its high absorptive powers. Xo one 
thing is guarded more zealously in every city than its 
water supply. Contamination of cisterns, springs and 
wells by cess pools or from similar sources is so easy 



34 CHEMISTRY FOR NURSES 

that the use of such water is seldom safe in any thickly 
settled community. Appearance of the water is no 
guide ; chemical and bacteriologic tests are the only 
way of knowing certainly and these should be appealed 
to whenever there is the slightest doubt in the matter. 

8. Nature's Method of Purification. — Sunshine and 
air are Nature 's greatest enemies to many impurities 
in water. In open, flowing streams, in a comparatively 
short time, sunlight and the oxygen of the air destroy 
the greater portion of impurities which find their way 
into the water by means of sewage. A noted example 
was brought to the attention of the public some few 
years ago when the city of St. Louis brought suit in 
the courts against Chicago, complaining that the latter 
city was contaminating the water supply of the former. 
This claim was based upon the fact that Chicago had 
dredged out the upper channel of the Chicago River, 
dug a canal acrossi to the Illinois River and was thus 
sending her sewage down to the Mississippi River in- 
stead of into Lake Michigan as formerly. Chemical 
experts employed in the case after making careful an- 
alyses testified that the sewage in crossing the state 
was entirely oxidized and purified before reaching the 
city of St. Louis. 

Notwithstanding this fact, typhoid and other disease- 
producing germs often withstand these forces of Na- 
ture and too great care can not be exercised in daily 
examinations of the water supply in every city. 

9. Methods of Purifying City Water Supply.— The 
method followed must naturally depend upon the source 
of supply. If this is a river, which often carries more 
or less material in suspension, settling basins or fil- 
tration beds or both must be installed. For a large city 
settling basins must be of very considerable size and 



WATER AND ITS COMPOSITION 35 

are divided into compartments. Into one or more, where 
the water with its load of mud in suspension is re- 
ceived from the river, a stream of milk of lime and a 
solution of aluminum sulphate or some similar sub- 
stance are run by gravity. These on coming together 
in the water produce a gelatinous coagulum which set- 
tles somewhat rapidly, carrying with it the mud and 
most of the bacteria, from the fact that they are gener- 
ally attached to mud particles. At intervals this de- 
posit is washed back into the river below the intake. 
The water is now clear but still may contain pathologic 
bacteria. Hence as it enters the great pipes on its final 
journey to the city it is treated with liquid chlorine, 
or chlorinated lime in solution, or some similar sub- 
stance, in small but sufficient amounts to render it 
perfectly safe for domestic use. Where filtration beds 
are used, these consist of basins or chambers with thick 
layers of sand over gravel or tiling through which 
the water filters, leaving its sediment behind. For 
large cities using water carrying a considerable amount 
of mud, a combination of settling basins and filtration 
beds is desirable. An idea of these may be obtained from 
Fig. 3. 

Another Problem. — In some portions of the country, 
the water supply is not obtained from running streams, 
but from reservoirs in mountain valleys or small lakes. 
Often in such cases another serious problem confronts 
the chemist. There is no sediment to be removed, but 
in the summer months certain algae, a species of plant 
to which the green scum seen on stagnant water be- 
longs, grow abundantly upon the surface; as autumn 
approaches, they produce spores which burst, rendering 
the water exceedingly offensive in odor. To prevent 
this such reservoirs now are treated with blue vitriol. 



36 



CHEMISTRY FOR NURSES 



A burlap sack filled with the copper sulphate crystals 
is suspended in the water from the stern of a skiff and 
two men row back and forth across the lake until the 
compound has all been dissolved. This may require 
several days. It has been found that the merest trace 
of blue vitriol in the water prevents the growth of the 
algae, yet at the same time will have no serious effect 
upon the human system. An instance of this is the 
famous Sweetwater Dam in Southern California, hold- 
ing billions of gallons of the finest water from the moun- 




Fig. 3. — Diagrammatic view of city water plant. B, the settling basin; F, 
the filter, in the bottom of which are layers of sand and gravel, indicated by 
the letters S and G. 



tain snows, sufficient for San Diego, National City and 
all the surrounding territory. 

10. Some Simple Tests for Water. — Many liquids re- 
semble water in appearance and sometimes it is impor- 
tant to determine positively whether they are water or 
some other compound. Pure water has no color, no 
odor, no taste, will not affect either red or blue litmus 
paper, leaves no residue on evaporation, and will turn 
anhydrous copper sulphate blue. It is often said that 



WATER AND ITS COMPOSITION 37 

pure water tastes flat ; this is because we are accustomed 
to drinking that which contains more or less foreign 
matter which really gives it some taste. The above tests, 
however, applied to any liquid resembling water will 
usually be sufficient to determine. 

Exercises for Review 

1. Give some of the familiar forms in which water occurs. 

2. Name some of the familiar food products with amount of 
water contained. 

3. What is the amount of water in the human body? 

4. Give the electrolytic proof for the composition of water. 

5. Why does the hydrogen go to the cathode? The oxygen to 
the anode? 

6. Describe the synthetic proof for the composition of water. 

7. What is deliquescence? Name two such substances. 

8. What is a hygroscopic substance? 

9. What is a hydrate? Water of combination? Give illus- 
trations. 

10. How may water of combination be removed? 

11. What is meant by anhydrous? How could you prepare 
anhydrous copper sulphate? 

12. What is efflorescence? Illustrate. 

13. What is hard water? How does it become hard? 

14. How may we know if water is pure for drinking? 

15. How does nature purify water in streams? 

16. Give some methods used by cities in purifying river water 
for use. 

17. What treatment is often necessary for water derived from 
lakes? 

18. Nanie some of the simple tests which may be applied for 
water. Would these give any evidence as to purity? 



CHAPTER III 

HYDBOGEN 

Outline — 

1. Brief History of the Gas. 

2. Hydrogen in Nature. 

3. Ways of Preparing Hydrogen — 

(a) From "Water, First by Electrolysis; Second, by 

Metals Like Sodium. 

(b) From Acids, Especially Sulphuric and Hydro- 

chloric, with Zinc or Iron. 

(c) By Heating Oils, Like Kerosene, in Absence of 

Air. 

4. Acids as a Source of Hydrogen. 

5. Characteristics of Hydrogen. 

6. Uses of Hydrogen — 

(a) In Oxyhydrogen Blowpipe; 

(b) In Balloons. 
Exercises for Eeviewi. 

1. Discovery of Hydrogen. — It is probable that the 
great physician chemist, Paracelsus, prepared hydro- 
gen. At least we may judge so from the fact that he 
carried out experiments involving the evolution of hy- 
drogen as a by-product. However, if he did, he made 
no study of the gas, and as he does not mention it in 
his writings, it possibly escaped his notice entirely. It 
was not till 1766 that Cavendish, the great English 
chemist, prepared and recognized in hydrogen a gas 
hitherto unknown and made a careful study of it. In 
accordance with the ideas of the time, from the fact 
that it is highly combustible, he gave it the name of 

38 






HYDROGEN 39 

inflammable air. Although it was Cavendish who first 
proved that water consists of hydrogen and oxygen, 
nevertheless, he did not regard it as an element and it 
was not until toward the latter part of the century that 
it was so recognized and received the name of hydrogen. 
meaning water producer. 

2. Hydrogen in Nature. — Although not found free 
upon the earth in appreciable quantities, hydrogen is 
a constituent of many compounds and is very widely 
distributed. First of these in importance is water, of 
which as already seen it is % by volume and % by 
weight. Second, it is found in all acids, many of which 
exist in nature: thus, citric acid in lemons and grape- 
fruit ; tartaric in green grapes ; oxalic in rhubarb, etc. 
Third, organic compounds, by which we now generally 
mean carbon compounds, of which considerably over 
100,000 have been prepared and studied. Familiar 
among these are sugar, starch, fats, oils, etc. 

3. Preparation of Hydrogen. — In preparing any ele- 
ment for study naturally we should expect to use some 
compound containing that element ; so in the present 
case we turn to one or more of the substances men- 
tioned in the preceding section. In another chapter we 
have already studied a method of obtaining hydrogen 
from water by electrolysis. While this way gives a 
very pure gas, with the apparatus at hand in the or- 
dinary laboratory, it is slow and expensive, hence sel- 
dom used as a source of hydrogen. 

It has been stated elsewhere that the elements may 
be divided roughly into two groups, electropositive and 
electronegative. Moreover, we have seen that hydro- 
gen is electropositive. At this time it must be stated 
further that some positive elements are more strongly 
positive than others. It is well known that a bar mag- 



40 



CHEMISTRY FOR NURSES 



net shows strong magnetism at the poles or ends, while 
the property rapidly diminishes toward the center. (See 
Fig. 4.) 

In a general way we may compare the metals to the 
positive half of the magnet. Starting with potassium 



K 

Na 
Ca 
Ug 
Al 
Zn 
Fe 
Sn 
Pb 
H 
Cu 

Au 




Fig. 4. — Electromotive series of metals. 

we have a very strongly positive element, next is so- 
dium, and so on until we ( come to hydrogen, tenth in 
number in the illustration. Following hydrogen are 
several other common metals, less positive. If we stop 
to think about it, remembering that all compounds are 
composed of a positive and a negative part, we should 



HYDROGEN 



41 



expect that, in water, for example, any metal more pos- 
itive than hydrogen would be able to deprive the 
hydrogen of its oxygen and set the hydrogen free. Now, 
potassium, very strongly positive, does this so violently 
that the heat generated is more than sufficient to ig- 
nite the gas instantly, volatilizing a small amount of 
the potassium and coloring the flame violet. Sodium, 
next in order, also decomposes water rapidly but on 
cold water not sufficient heat is generated to ignite the 
hydrogen, although this will happen if the water has 
been previously warmed. As we go down the scale the 
action is less and less rapid, some requiring boiling 




Fig. 5. — Preparing hydrogen from water. 

water, while those near hydrogen act very, very slowly. 
A convenient method of collecting hydrogen when 
sodium is used is shown in Fig. 5. A small piece of 
sodium is enclosed in the gauze spoon and placed under 
a test tube or small bottle full of water inverted over 
a trough of water. Bubbles of gas rise rapidly from 
the water and fill the tube. To show that the gas is 
hydrogen it may be lit and will be seen to burn with an 
almost invisible flame as was the case in the electrolysis 
experiment. In this connection it is interesting to note 
that a bit of sodium dropped upon a dish of water rolls 
around, gradually becoming smaller. By touching a 



42 



CHEMISTRY FOR NURSES 



lighted candle to the metal the hydrogen catches fire 
and burns with a yellow flame due to the volatilization 
of a small amount of the sodium. 

4. Acids as a Source of Hydrogen. — Neither of the 
methods outlined above for obtaining hydrogen from 
water is well suited where considerable quantities are 
desired. Acids are found far preferable: however, such 
acids as hydrochloric and sulphuric instead of the or- 
ganic ones previously mentioned are used. As in the 
case of water, a metal is used to displace the hydrogen 
and for the same reason. Experiment has shown that 
the metals higher up in the series act too violently with 




Fig. 6. — Preparing hydrogen from acids. 

the acids named ; moreover they are very expensive. 
Therefore, zinc, sixth in the series, or iron, seventh, is 
more often used, the former giving the purer gas and 
therefore preferred for class study. The method is 
shown in Fig. 6. F is a generating flask of about 250 
c.c. capacity; it is fitted with a two-hole cork; thistle 
tube, T; elbow, E, rubber connection, R; delivery tube, 
D. Several bottles are filled with water and inverted 
over the pneumatic trough, P. When everything is 
ready, sufficient mossy zinc is put into the flask to cover 
the bottom, the cork is replaced snugly, water is poured 



HYDROGEX 43 

through the thistle tube to cover the zinc, and seal the 
tip of the thistle tube, then sulphuric acid is added, a 
small amount at a time till the action begins. A large 
amount of acid will stop the action almost entirely. 
The process may be hastened greatly by pouring in a 
few cubic centimeters of a solution of copper sulphate. 
The first bottle collected will be mostly air and should 
be discarded. 

5. Characteristics of Hydrogen. — From the experi- 
mental study of hydrogen it will be learned that it is a 
colorless gas, odorless, lighter than air, not soluble in 
water, is very inflammable, explosive when mixed with 
air, and extinguishes a flame when inserted into a mass 
of it, or as it is generally expressed, does not support 
combustion. More detailed experiments have shown 
that hydrogen is the lightest of all gases, being only a 
little more than one fifteenth as heavy as air. It re- 
quires over eleven liters of it, about eleven quarts, to 
weigh one gram, the weight of one liter being a little 
less than .09 gram. It burns with an intensely hot 
flame, one gram of it producing more than four times 
as many heat units as an equal weight of anthracite 
coal. It easily passes through unglazed earthenware, 
or the crack of a bottle that will not leak water or 
other gases, and toy balloons filled with it soon lose 
their buoyancy for the reason that the hydrogen escapes 
through the pores of the rubber itself. It is rapidly 
absorbed by certain metals, as platinum and palladium, 
especially the latter, producing heat. This is called 
occlusion and so much heat is generated that a platinum 
sponge lowered into a bottle of hydrogen and oxygen 
mixed, will almost instantly explode the mass with 
violence. 

6. Uses of Hydrogen. — (a) The Oxyhijdrogen Blow- 



44 CHEMISTRY FOR NURSES 

pipe or Torch. — There are several patterns of the oxy- 
hydrogen blowpipe, but they all amount to the same 
thing. They have one pipe which introduces a supply 
of oxygen within another pipe furnishing hydrogen, at 
a point shortly before that at which the mixture is to 
be burned. It gives an intensely hot flame, ranging 
from 2,000° to 2,500° C, 3,600° to 4,500° F., and is 
used in melting refractory metals or other substances. 
Up to the introduction of the electric arc light, the 
calcium, or Drummond, or limelight, by all of which 
names it is known, was used almost exclusively for 
stereopticon work and stage lighting. This was se- 
cured by allowing the flame of the blowpipe to impinge 
upon a prepared stick of lime, which became white hot, 
dazzling in brightness. See Fig. 7 for a common type. 




Fig. 7. — Oxyhydrogen blowpipe. 

(b) Use in Balloons. — At the present time observa- 
tion balloons and dirigibles are using immense quan- 
tities of hydrogen and serving a valuable purpose. 
Natural gas is sometimes used instead of hydrogen, but 
it is about eight times as heavy, hence not nearly so 
desirable. Sometimes from amusement parks or county 
fairs balloons are sent up, from which the aeronaut 
after a short time jumps with a parachute. As he does 
so, usually the balloon capsizes and a puff of smoke ap- 
pears. This is understood when it is known how such 
balloons are usually filled. At the beginning of this 
chapter it was stated that organic compounds, such as 
oils, all contain hydrogen. So, for such brief flights, 
kerosene, or some similar oil, is run in gradually upon 






HYDROGEN 45 

a bed of hot coals in a furnace with draughts closed to 
exclude the air. The heat decomposes the oil into a 
number of gases, about 45 per cent of which is hydro- 
gen and these are passed by a pipe into the balloon. 
Smoke is always an indication of imperfect combustion, 
; and in this case that seen is due to the partial combus- 
f tion of a small amount of the oil owing to the fact 
that it is impossible to keep out all traces of air. 

Exercises for Review 

1. By whom and when was hydrogen discovered? What did he 
call it? Why? 

2. When did it receive its present name? Why? 

3. Name three classes of substances containing water. Give 
proportion in most abundant one. 

4. How may hydrogen be obtained from water? Give two 
j ways. 

5. What may be said of the purity of the gas obtained this 
| way? "What may be said of the value of these methods for ob- 
taining large amounts? 

6. What is said about the electromotive series of metals? 
Where does hydrogen come in this series? 

7. What is true of any metal before hydrogen in the series? 
After hydrogen? 

8. Illustrate with potassium; with copper. 

9. Describe method of obtaining hydrogen from water by 
sodium. 

10. What is the best way to prepare large amounts of hydro- 
gen? What acids are best? 

11. What metals are used with these acids? Why not sodium? 

12. Give six characteristics of hydrogen. 

13. What is said of the heat obtained from burning hydrogen? 
What application is made of this fact? 

14. What use is made of hydrogen because of its lightness? 
What substitutes may be used? What disadvantage has each? 



CHAPTER IV 
THE ATMOSPHERE 

Outline — 

1. Various Ideas of the Air. 

(a) In Time of Aristotle. 

(b) In Eighteenth Century. 

2. Composition of the Air. 

(a) Components. 

(b) Amounts of Each. 

3. Proofs that the Air is a Mixture. 

(a) Absorption of Its Components by Water. 

(b) Evaporation of Constituents from Liquid Air. 

4. Components Remain Mixed, Why. 

(a) Densities of the Constituents. 

(b) Possible Arrangement of Constituents. 

(c) Wind Currents. 

(d) Diffusion of Gases. 

5. Value of the Oxygen. 

(a) Warming the Human Body. 

(b) Problems of a Plentiful Supply. 

(c) Amounts Required. 

6. Purpose of the Carbon Dioxide. 

(a) Its Effect upon Animal Life. 

(b) What Indicated by Large Amounts in a Room. 

(c) How Used by Plants. 

(d) The Oxygen Cycle in Nature. 

7. Carbon Dioxide and Plant Life. 

8. The Moisture in the Air. 

(a) Saturation — Amounts Possible at Different 

Temperatures. 

(b) Effect of High Humidity on Body. 

(c) Problem of Supplying Moisture in Winter. 

(d) Effects of Lack of Moisture. 

9. The Health Problem. 

46 



THE ATMOSPHERE 47 

10. Value of the Nitrogen. 

(a) As a Diluent. 

(b) In Nitrogenous Compounds for Body. 

(c) How Secured for Fertilizer. 
Exercises for Keview-. 

1. Early Ideas Regarding the Air. — As long ago as 
the time of Aristotle, 350 years before Christ, the air 
was a subject of interest to scientists. In that day, as 
already stated, it was regarded as one of the four pri- 
mary substances; and as they did not seek scientific 
truth by experimental investigation, for centuries noth- 
ing new was learned concerning it. In the latter half 
of the eighteenth century, however, a number of chem- 
ists, especially in England, France, and Sweden, were 

| engaged in a study of the air, various other gases and 
combustion. But even as late as the time of the Amer- 
ican Revolution the idea that the gases already discov- 
ered were simply modifications of the air had not en- 
tirely passed away. Joseph Black, the discoverer of 
carbon dioxide, called it fixed air; Cavendish named 
hydrogen, inflammable air; Priestley called oxygen, cle- 
pJilogisticated air; Scheele called it fire air; nitrogen 
was known as phlogisticated air; even the perfumes ex- 
haled by the flowers were regarded as modified forms of 
the atmosphere. It was not until near the end of the cen- 
tury that Lavoisier, the great French chemist, applying 
the careful use of the balance, overthrew the prevalent 
ideas of combustion, gave the present names to hydro- 
gen and oxygen, and cleared the chemical atmosphere 
of much that was false and detrimental to progress. 

2. Composition of the Air. — For a good many years 
after the air was known to contain several substances, 
it was not thought of as a mixture ; or at least the two 
more important constituents were regarded as com- 



48 CHEMISTRY FOR NURSES 

bined and this compound mixed with the others of lesser 
value. Now, however, we know that the air is a mix- 
ture, consisting of nitrogen, oxygen, carbon dioxide, 
argon, and watery vapor, with very small amounts of 
several other rare elements. These five are in the fol- 
lowing proportions by weight: nitrogen, 75.46 per cent; 
oxygen, 23.18 per cent; argon, 1.29 per cent; carbon 
dioxide, 0.04 per cent; vapor, variable. 

3. Proof That the Air Is a Mixture. — Several very 
convincing proofs may be offered that the air is a 
mixture. First, if pure water is exposed to air, it is 
found that the water absorbs relatively much more 
oxygen than nitrogen, although there is nearly four 
times as much nitrogen in the air: if the air were a 
compound the absorbed portion would necessarily con- 
tain the constituents in the same proportion as found 
in the undissolved part. Moreover a given volume of 
water will absorb the same amount of oxygen whether 
it be exposed to air or pure oxygen; the same is true 
of the nitrogen absorbed. This shows that these gases 
must be free in the air to act as if they were not to- 
gether at all. 

Second, when air is liquefied and allowed to stand in 
an open vessel, practically all the nitrogen will boil 
out leaving nearly pure oxygen, while the carbon diox- 
ide becomes a solid and may be filtered out. Since nitro- 
gen has a lower boiling point than oxygen this is pos- 
sible, just as alcohol with a boiling point of about 
78° C. may be removed from water with a boiling point 
of 100° C. However, if the nitrogen and oxygen were 
combined in the air, they would necessarily evaporate 
in the same proportions as contained in the liquid. 

4. Why Do the Constituents Remain Mixed? — The 
gases of the atmosphere have densities differing greatly. 






THE ATMOSPHERE 49 

Ajgon is the heaviest, with a density compared with 
hydrogen of about 40 ; carbon dioxide is next, with a 
density of 22; oxygen, third, density, 16; nitrogen, 
fourth, 14; watery vapor, 9. If not mixed, argon so 
heavy, would lie next to the ground to a depth of some 
200 feet; the carbon dioxide above the argon, ten or 
twelve feet deep; the oxygen next, about one mile and 
then the nitrogen about four miles. This is on the as- 
sumption that the air is everywhere the same density 
instead of becoming rarer as we ascend. AVere such 
conditions to obtain it is evident no life upon the globe 
would be possible. Two things prevent such an ar- 
rangement: one is the wind currents more or less preva- 
lent everywhere which maintain a constant circulation. 
Another is what is called diffusion of gases. By this 
is meant that the particles of gas in any closed space 
free from currents are quickly carried from one portion 
of the space to another. Thus in a closed room, if an 
irritating gas is generated in one corner it is soon per- 
ceptible in all parts of the room, regardless of whether 
the gas is light or heavy. 

5. Human Value of Each Constituent. — The oxygen, 
constituting about one fifth of the air, is an absolute 
essential for respiration. When taken into the lungs it 
is absorbed by the blood and forms there a kind of 
loose compound somewhat similar to water of combina- 
tion in hydrates and is thus carried to all parts of the 
body. In this way the average human being uses daily 
an actual weight estimated about 750 grams, or 26 
ounces of pure oxygen. Meeting the carbon in the tissues, 
chemical union takes place : carbon dioxide is the result 
to the amount of about 1,000 grams, or over two pounds, 
Accompanying this chemical action or as a result of it. 



50 CHEMISTRY FOR NURSES 

heat is produced and the body warmed. When the air 
enters the lungs it is about 23 per cent oxygen by 
weight; when it leaves, it is only about 16 per cent ox- 
ygen, while the carbon dioxide has been increased more 
than one hundred fold. To be more specific, ordinary 
air contains from 3 to 4 parts of carbon dioxide in ten 
thousand or from .03 to .04 per cent. On leaving the 
lungs it contains about 440 parts per ten thousand or 
4.4 per cent. It will be seen, therefore, that in a 
crowded room with poor ventilation the percentage of 
carbon dioxide rapidly increases. In the ordinary home 
of the middle and upper classes where the family is 
usually small, by means of the air leakage from ill- 
fitting windows and doors there is usually ample ven- 
tilation. It is in the densely populated tenement 
houses of few rooms, kept none too well, where the 
danger lies; also in school rooms where many children 
are gathered and in various other places of public 
gathering such as theatres and moving picture houses 
where the rooms are tightly closed and the ventilation 
is poor. The health boards of many states require in 
school rooms a system of ventilation which will furnish 
30 cubic feet of fresh air per minute per pupil. It will 
be noticed from what was stated in a preceding section 
that in the first respiration about one fourth of the ox- 
ygen is removed ; it is approximately true that a second 
respiration of the same air removes about a fourth of 
what remains: it is evident, therefore, what the effect 
of an impoverished air would be upon the purification 
of the blood, and the importance of a plentiful supply 
of fresh air. 

6. The Carbon Dioxide. — Carbon dioxide is not a 
poison and the amounts found in any ordinary room 



THE ATMOSPHERE 51 

could not produce serious results. A person drowns in 
a well of carbon dioxide just as he does in one of water, 
simply because oxygen is shut off from the lungs, and 
not because of any toxic effects of the gas. A high per- 
centage of carbon dioxide, however, is nearly always in- 
dicative of poor ventilation and therefore of the pres- 
ence of large amounts of other gases thrown off from 
the lungs which are injurious. All expired air con- 
tains not merely the carbon dioxide but various other 
substances, the result of broken down tissue and it is 
these accompanying products which are to be feared. 
In breweries where the percentage of carbon dioxide 
often runs relatively high because it is being evolved 
in the processes of manufacture, none of the symptoms 
observed in poorly ventilated crowded rooms appear; 
this is because the carbon dioxide present is not ac- 
companied by the noxious gases from the products of 
respiration as in the other case. 

7. Carbon Dioxide and Plant Life. — Carbon dioxide 
is an absolute essential of plant growth. Through 
their leaves all growing plants inhale it and, decompos- 
ing it under the influence of sunlight, they store up 
the carbon in the woody structure in the form of cel- 
lulose, while the oxygen is thrown off again to the air. 
So while in various ways vast quantities of carbon di- 
oxide make their way into the air, in the endless cycle of 
nature it is being constantly removed by plants and the 
oxygen necessary for animal life is being restored again. 

8. Necessity of Moisture. — The amount of moisture 
the air can hold depends upon the temperature. For 
example, a cubic meter of air at 0° C. (32° F.) is able to 
hold only 4.87 grams of water; at 10° C, 9.92; at 20°, 
17.16. At these temperatures if it contains the amount 



52 CHEMISTRY FOR NURSES 

mentioned it is said to be saturated. Quantities rang- 
ing between two thirds and three fourths of these 
amounts are regarded as most suitable for health con- 
ditions. High temperatures with high humidity, as is 
frequent in the Mississippi Valley and Atlantic States 
in summer, are often attended with serious results, 
while the same temperatures in the .Rocky Mountain 
States are not found even uncomfortable. The reason 
for this is evident. The temperature of the human body 
is regulated by evaporation of moisture from the sur- 
face; if the surrounding atmosphere is near the point 
of saturation the moisture upon the body is not carried 
away, the cooling process is stopped and oppression 
results. To evaporate a single gram of water requires 
something less than 550 calories of heat; or the heat 
required for the evaporation of an ounce of water if 
taken from the surface of the body weighing 150 
pounds would lower the temperature of the entire body 
about 0.5 of a degree. 

9. The Health Problem. — These facts indicate a prob- 
lem of healthfulness in our homes and public build- 
ings. Assuming 32° F. (0° C.) as the average tempera- 
ture of an ordinary winter day, if saturated a cubic 
meter of air could contain but 4.87 grams of moisture. 
Very seldom in winter except in certain localities does 
the air approach saturation, more often not over 50 
per cent, or less. When this air is heated to 20° C. 
(about 68° F.) the humidity would be as low as 15 per 
cent oftentimes. The result is rapid evaporation of the 
moisture of the body, chapped hands, dry and irritated 
nasal passages, throat and bronchial tubes. To remedy 
this is a difficult problem. In large school buildings which 
are warmed to a greater or less extent by an indirect 



THE ATMOSPHERE 



53 



system of heated air forced into the various rooms, 
means are provided for materially increasing the mois- 
ture. In homes warmed by steam or hot-water radi- 
ators a towel rack such as is found in every bath room 
can be fastened on the wall behind each radiator, with 
a towel suspended therefrom and dipping in a pan of 
water upon the floor. By capillary attraction the water 
will be drawn up into the towel and then rapidly evap- 
orated by the heat. In houses heated by hot-air fur- 




Fig. 8. — Nodules in which the nitrogen-fixing bacteria live on the roots of 
a bean. (From Warren — Elements of Agriculture.) 



naces, which are the more common, the problem is more 
difficult. In many cases, however, an aluminum wire 
may be fastened beneath the register and a short towel 
suspended in a pan of water. The main trouble is to 
keep the pans supplied with water, for the evapora- 
tion is surprisingly rapid. 

10. Value of the Nitrogen. — As found in the air in 
a free state, nitrogen seems to serve little purpose other 



54 CHEMISTRY FOR NURSES 

than as a diluent for the oxygen. "With the air largely 
oxygen no fire could be kept under control, and the 
human body as at present organized in all probability 
would not long remain in health. In the form of com- 
pounds, however, nitrogen is of inestimable value. 
The muscular part of the body is built up of nitrogen 
compounds and can be repaired only by nitrogenous 
foods. "We can not obtain nitrogen directly from the air 
and must go either to the plant or the animal kingdom. 
Moreover, plants can not obtain it directly from the air; 
to them it must be supplied by soluble fertilizers, which 
will be considered in another chapter. It should be 
said, however, that one class of plants, the legumes, 
have the power, through bacteria which form nodules 
upon the roots, of absorbing nitrogen directly from the 
air. Such plants are able not only to make use of this 
supply themselves, but if plowed under, they leave it in 
soluble form for other crops. At the present time large 
areas every year are sowed to cow peas, soy beans, 
vetch, and various clovers, mainly for the nitrogen-fix- 
ing results which follow. See Fig. 8 showing nodules 
upon the root of a bean plant, 

Exercises for Review 



1. What was the idea regarding the air in time of Aristotle! 
Why was so little learned abont it for so many centuries? 

2. In eighteenth century what relation was supposed to exist 
between various gases known and the air? Illustrate by names. 

3. What chemist did most at clearing up the difficulties? 

4. What are the constituents of the air and their proportions? 

5. Give two strong proofs that the air is a mixture. 

6. If in order of their densities how would the gases in the 
air be arranged? Give their densities. 

7. What two things prevent such an arrangement? 

8. State what is meant by diffusion and illustrate. 



THE ATMOSPHERE 55 

9. Explain fully the value of oxygen to the human body. 

10. Give difference in composition of the air before being in- 
haled and just after exhalation, 

11. What amount of fresh air is deemed necessary in school 
rooms? How is this secured in private homes? 

12. What is the effect of carbon dioxide upon the body? 

13. What does a high percentage of carbon dioxide in a room 
usually indicate? 

14. Where does the danger lie in such conditions? 

15. Explain what use plants make of carbon dioxide. 

16. Show how equilibrium of oxygen is maintained by the 
cycle in nature. 

17. What governs the amount of moisture the air can hold? 

18. What is meant by saturation? 

19. Air saturated at 0°C. would be what percentage saturated 
at 10 °C? What at 20 °C.? 

20. Explain how the body is cooled and the effect of high hu- 
midity. 

21. Why does an electric fan cool the body when it does not 
furnish air any cooler than that near the body? 

22. What is the effect upon the body of a very dry atmosphere? 

23. How may conditions be improved in our homes? 

24. State some benefits which may result from a very dry 
atmosphere. Why? 

25. What is the main use of free nitrogen in the air? 

26. What use is nitrogen in the body? How secured? 

27. How do plants secure their nitrogen? 

28. What are legumes? How do they serve as nitrogen-fixing 
plants? 



CHAPTER V 

OXYGEN 

Outline — 

1. History of Oxygen. 

(a) Date of Discovery. 

(b) Names of Discoverers. 

(c) Old Names for the Gas. 

2. Occurrence of Oxygen in Nature. 

(a) In YV~ater. 

(b) In the Air. 

(c) In the Earth's Eocky Crust. 

(d) In the Human Body. 

3. Preparation of Oxygen. 

(a) From Water, by Electrolysis. 

(b) From Mercuric Oxide. 

(c) From Potassium Chlorate, with a Catalyst. 

4. Experiments with Oxygen. 

(a) Burning Phosphorus. 

(b) Burning Charcoal. 

(c) Burning W*atch Spring, etc. 

5. Characteristics of Oxygen. 

6. Uses of Oxygen. 

(a) Respiration. 

(b) Combustion. 

(c) Medical. 

7. Oxygen as Belated to Health. 

(a) In Purifying Waters, 

(b)~ In Destroying Noxious Gases in the Air, 

(c) In Eemoving Waste Through Decay, 

8. Kindling Temperature. 

9. Oxidation and Combustion. 
Exercises for Review'. 

56 



OXYGEN 57 

1. Discovery of Oxygen. — In 1773 or perhaps a little 
earlier, Scheele, a great Swedish chemist, using 
manganese dioxide and sulphuric acid, prepared ox- 
ygen and carefully studied its properties. In August 
of 1774, Joseph Priestley, an English chemist, who 
later in life moved to America, prepared oxygen by 
heating mercuric oxide. He gave it the name of 
dephlogisticated air, whereas Scheele had called it fire 
air and life air, from the fact that he had found it nec- 
essary for both. Priestley published an account of his 
investigations shortly after making them, while Scheele 
did not do so, hence the former has generally been re- 
garded as the first discoverer. It was not for some years 



Oxygen 50 % 


Silicon 25 7. 


E 

< 


u I s - 


s 


1 £ 



Fig. 9. — Abundance of certain elements. 

after this that the present name, oxygen, meaning acid 
former, was suggested by Lavoisier. 

2. Occurrence of Oxygen. — Oxygen constitutes about 
half of all the material in the world. By weight, water 
is nearly 90 per cent oxygen ; the air about 23 per cent ; 
sandstone, somewhat more than 50 per cent; limestone, 
48 per cent ; the human body, about 66 per cent ; while 
nearly all the elements form compounds with it. Fig. 
9 gives an idea of its relative abundance. 

3. How May Oxygen Be Prepared? — Either method 
used by the discoverers of oxygen may be used and 
sometimes both are. It may also be obtained, as we 
have seen, by the electrolysis of water. However, a 
much easier way than any of these and one yielding it 
more abundantly is by using a compound called potas- 



58 



CHEMISTRY FOR NURSES 



sium chlorate. If a small amount of this, say a half 
inch in a test tube, be heated, it will be seen to melt first, 
then shortly begin to boil, and soon thereafter oxygen 
will fill the tube and ignite a glowing pine splinter held 
at the mouth. If now into another similar test tube 
the same amount of potassium chlorate is mixed with 
about one-third or half as much manganese dioxide, and 
heated in the same way as before, it will ignite the 
pine splinter in from one-fourth to one-sixth the same 




Fig. 10.-— Preparing oxygen from potassium chlorate. 

length of time. Further experiments, made after all 
the oxygen has been driven off show that the manga- 
nese dioxide has not changed at all; it is still all pres- 
ent, may be recovered and used repeatedly equally as 
well as the first time. All it has done is to hasten the 
chemical action by its presence: such a substance is 
called a catalyst, and the process is catalysis. It will be 
found later that many such cases occur in chemistry. 
Likewise, these catalytic agents exist in the human body 
in the form of enzymes whose purpose it is to hasten 



OXYGEN 



59 



the processes of digestion, also in other places in na- 
ture. 

For laboratory purposes, oxygen is usually prepared 
by this method. Fig. 10 shows the usual way of collect- 
ing the gas. T is a six- or eight-inch test tube about one 
third full of potassium chlorate and manganese dioxide, 
well mixed, in the proportion of about four parts of 
the former to one of the latter. When the receiving 
bottles are ready in the pneumatic trough, gentle heat 
is applied until the gas is coming off freely when it is 




Fig. 11. — Preparing oxygen from sodium peroxide. 

removed until needed again to hasten the action. If 
only a small amount is desired it may be obtained from 
a compound of sodium called "oxone" which can now 
be purchased at the supply houses. No heat is neces- 
sary as the gas is readily evolved by allowing water to 
drip upon it. (See Fig. 11.) 

4. Some Experiments With Oxygen. — (a) Phos- 
phorus ignited in a deflagrating spoon and lowered into 
a large bottle of oxygen burns with a dazzling white 
light. 



60 CHEMISTRY FOR NURSES 

(b) A piece of bark charcoal, fastened on a wire, and 
heated till it begins to glow, in a bottle of oxygen, 
bursts into a shower of sparks. 

(c) Sulphur, which burns with an almost invisible blue 
flame in the air, in oxygen is much brighter and deeper 
blue color. 

(d) A watch spring, from which the temper has been 
drawn by heating, if kindled with sulphur, burns rap- 
idly with a bright display of sparks. These and many 
other experiments which might be mentioned all show 
the vigor with which oxygen combines with a large 
number of substances when heated somewhat above or- 
dinary temperatures. 

5. Characteristics of Oxygen. — If the above experi- 
ments are made carefully the following characteristics 
will be noticed: that it is a gas, colorless, odorless, 
heavier than air, shown by the fact that when using a 
bottle of it, it is left sitting upright upon the table, ap- 
parently not soluble in water, combines vigorously with 
most substances, in contact with the air does not burn. 
In reality it is somewhat soluble in water, three vol- 
umes being absorbed by 100 of water. It is this free 
oxygen in the water that fishes and other aquatic ani- 
mals use. It may be liquefied about 182 degrees below 
zero centigrade and in this condition resembles water 
except that it is pale blue in color. It is usually said 
that the gas is colorless but probably what we call the 
"blue sky" is nothing more than the color of the miles 
of gaseous oxygen in the air. 

6. Uses of Oxygen. — Primarily, it should be said that 
oxygen is necessary for respiration. As we have seen, 
the warmth of the body is due to the combination of 
the oxygen received through the lungs with certain ma- 
terials derived from our food. Animals with highly 



OXYGEN 61 

developed lungs, using an abundance of air, are warm 
blooded and need much food to supply the wastage. 
Others, such as snakes, with partially developed lungs. 
and fishes with gills, using very small amounts of ox- 
ygen, are cold blooded and need but little food. All who 
have ever kept a canary bird and a gold fish, not dif- 
fering greatly from each other in weight, must have 
noticed the amount of food required in the two cases. 

Second, oxygen is necessary for all forms of ordinary 
combustion. Without fire civilization would have been 
impossible. At the present time we are able to do much 
I by the application of water power to electric gener- 
ators, but without fire primitive man could never have 
| made such a machine. Without fire he would never 
have been able to smelt the various metals from their ores ■ 
could never have made his steel tools; there would be 
no steam railways, steamships, nor any of the con- 
veniences of modern civilized life ; in short, he must 
have remained in the barbarism of the stone age. 

Third, oxygen is now used frequently in a medicinal 
way. The pulmotor is a familiar appliance in every 
hospital for use in cases of drowning, asphyxiation, 
electric shock, etc., to induce artificial respiration. 
After explosions in mines and buildings, or in smoulder- 
ing fires, the oxygen helmet enables the rescuing par- 
ties or firemen to go where they otherwise could not 
and is often thus the means of saving human life. Again 
in crises of disease, oftentimes, where there is great 
weakness, air enriched with oxygen, given artificially 
often sustains the patient till the greatest danger is 
passed. 

7. Oxygen and Health. — When the nerves of the 
human body are exposed to the air from any cause as 
in the case of a burn or wound of any sort, it is prob- 



62 CHEMISTRY FOR NURSES 

ably the action of the oxygen that produces the pain. 
The logical suggestion, therefore, after cleansing the 
wound, or if it be a chemical burn, after treating with 
the proper antidote to remove all traces of the offend- 
ing agent, is to protect from the air by some such ma- 
terial as olive oil or by some of the other equivalent 
methods of modern nursing. In all cases the exclusion 
of the air is effected. From this and from the fact that 
oxygen is usually necessary in decay and decomposi- 
tion, it might be thought that oxygen has a harmful 
as well as a useful side. Such is hardly the case, how- 
ever. We have already seen how polluted waters are 
purified. So also is the air. From time immemorial 
foul gases of all sorts have been escaping into the air, 
sufficient, ages ago, to render it unfit for respiration, 
had they not been destroyed. But the oxygen is ever 
combining with these, so that under ordinary condi- 
tions the air is as pure and fresh today as it was in the 
time of man's infancy. Moreover, were it not for the 
disintegrating action of oxygen upon all waste matter, 
refuse of every sort, the accumulation long ago would 
have been beyond human endurance. So, while in oc- 
casional cases from its very nature oxygen may cause 
the exposed nerve to smart and tingle, its values to 
health are so beyond all comprehension that we can 
think only of its beneficent side. 

8. Kindling' Temperature. — By kindling temperature 
is meant the temperature at which a substance takes 
fire or begins to burn. In the oxygen experiments 
mentioned above the sulphur and phosphorus needed 
very little heat to ignite them, while the iron had to be 
well kindled and even then began to burn with some 
difficulty. Yellow phosphorus has perhaps the lowest 
kindling temperature of any substance with which most 



OXYGEN 



63 



of us are familiar, in that very little friction is amply 
sufficient to ignite it. Sulphur and paraffine are a lit- 
tle higher, paper and wood somewhat higher, and so on. 
To show that the kindling temperature of paper is con- 
siderably above the boiling point of water, a very sim- 
ple, interesting experiment may be made. Fill an or- 
dinary paper, sanitary drinking cup about one-third 
full of water and suspend it on a ring stand as shown 




Fig. 12. — Boiling water in paper cup. 



in Fig. 12. Place a Bunsen burner under it with the 
flame playing directly upon the cup, but not lapping up 
over the sides. In a few minutes the water will boil 
vigorously. It is better if a cup not coated with paraf- 
fine can be used as its kindling temperature is much 
lower than that of paper and sometimes the drops of 
melted wax that run down will become scorched. The 
paper, however, remains unburned. 

9. Oxidation and Spontaneous Combustion. — When- 



64 CHEMISTRY FOR NURSES 

ever any substance combines with oxygen the process 
is called oxidation, although to the chemist the term 
has a broader meaning. It may be slow or rapid: if 
sufficiently rapid to produce light and perceptible heat, 
it is called combustion. This often takes place spon- 
taneously. If a small piece of yellow phosphorus is 
dissolved in carbon disulphide and poured upon a filter 
paper upon a ring stand, within a very few seconds after 
the liquid has evaporated sufficient heat is produced by 
the slow oxidation of the minute particles of phos- 
phorus spread over the paper to ignite it spontaneously 
and the whole bursts into flame. Likewise, certain oils, es- 
pecially linseed, in waste or rags, soon begin to oxidize ; 
the heat accumulates till often, after some hours, the 
kindling temperature is reached and the mass begins 
to burn. All waste of an oily character, therefore, 
should be thrown into air-tight metal cans to be kept 
there until disposed of in some safe manner. Again, 
it is common at coal mines to see the dump on fire. This 
is brought about spontaneously. In such cases there 
is usually more or less iron pyrite present, which be- 
coming wet by the rains begins to oxidize, whereby 
sufficient heat is generated to set on fire the small 
amounts of coal contained in the refuse from the mine. 
The same thing occasionally happens in coal bins es- 
pecially on ship-board where the amount stored is large 
and the ventilation poor so that the heat tends to ac- 
cumulate. 

Exercises for Review 

1. Name the two discoverers of oxygen with dates of their 
work. 

2. What names were given to oxygen at first? Why so given? 
Why called oxygen? 



OXYGEN 65 

3. About what part of the world does oxygen form? 

4. State briefly how oxygen is distributed in nature. 

5. What method may be used for obtaining oxygen from water ? 

6. What did the original discoverers use in making oxygen? 

7. What is the best way of preparing oxygen abundantly? 

8. What is a catalyst? Catalytic action? Illustrate. 
'9. What four experiments with oxygen can you give? 

10. What is the main purpose of these experiments? 

11. Name seven characteristics of oxygen. 

12. Of what value is the free oxygen found in water? 

13. Name three important uses of oxygen; what are the medi- 
cal uses? 

14. What is the action of the oxygen upon foul gases? Upon 
waste matter? 

15. What is meant by kindling temperature. Give four illus- 
trations. 

16. How may it be shown that the kindling temperature of 
paper is not low? 

17. Define oxidation; combustion. 

18. W T hat is the explanation of spontaneous combustion? Illus- 
trations? 



CHAPTER VI 
OZONE AND HYDROGEN DIOXIDE 

Outline — 

1. Allotropic Forms of Elements. 

(a) Oxygen and Ozone. 

(b) Diamond and Graphite. 

(c) Yellow and Eed Phosphorus. 

2. Characteristics of Ozone. 

3. Ozone in Nature, Produced How. 

(a) By Slow Oxidations. 

(b) By Electrical Discharge in Air. 

4. Preparation in Class Eoom. 

(a) By Slow Oxidation of Phosphorus. 

(b) In Preparing Oxygen from Potassium Perman- 

ganate. 

5. Practical Uses. 

(a) In Sterilizing City Water Supplies. 

(b) In Purifying Air for Public Buildings. 

(c) In Cleansing Wheat for Milling. 

6. Hydrogen Dioxide — Commercial Forms. 

7. Characteristics. 

8. Uses. 

9. Test for Ozone and Peroxide. 
Exercises for Eeview. 

Ozone 

1. What Is Ozone? — There are several of the elements 
which occur in nature in more than one form. Thus, 
the diamond and graphite, both familiar to every one, 
the latter in the so-called lead pencil, are two very dis- 
similar forms of carbon. In the study of oxygen two 

66 



OZONE AND HYDROGEN DIOXIDE 67 

forms of phosphorus, red and yellow, have been seen, 
one of which is kept under water, while the other needs 
no such protection. So, ozone is but another form of 
oxygen. The term allotropic is often used in such cases, 
and the less common form is called the allotrope. Thus 
ozone would be an allotropic form or allotrope of oxy- 
gen. In cases where one is about as common as the 
other each variety may be spoken of as the allotrope of 
the other. Ozone is really condensed oxygen, three vol- 
umes being condensed into the space of two. Thus 60 
volumes of oxygen would, if it all could be made into 
ozone, form only forty volumes. However, ozone is 
very unstable and is constantly changing back into the 
common form; hence, after a relatively small portion 
of any volume of oxygen has been converted into ozone, 
the process becomes reversible at a speed not differing 
greatly from the direct action and the quantity of ozone 
from that time on will not materially increase. 

2. Characteristics of Ozone. — Ozone has a peculiar 
odor, somewhat irritating if strong. It was through its 
odor that it was discovered, the name being derived 
from a Greek word, meaning to emit odor. It is always 
noticeable about strong electrical discharges, hence in 
x-ray work, wireless telegraphy, and similar operations, 
the air always becomes heavily charged with this al- 
lotropic form. It is much more active than ordinary 
oxygen, attacks the throat and bronchi if inhaled 
deeply and tarnishes quickly various metals such as 
silver and mercury which remain unchanged in the air. 

3. Ozone in Nature. — Ozone is produced during all 
electrical storms and for some unknown reason in slow 
oxidations. It is strongly germicidal and in this way 
is valuable in nature in purifying the air. It is possible 



68 



CHEMISTRY FOR NURSES 



that some of the valuable uses of oxygen in nature al- 
ready mentioned, may be due to the more active allo- 
tropic form of ozone. 

4. Preparation. — Sufficient ozone to give a good test 
may be obtained by allowing a stick of freshly scraped 
yellow phosphorous to remain partly exposed, for a 
few minutes, to the air in a closed bottle. Another easy 
method for obtaining sufficient quantities to be decid- 



nduciion 
coil 




NNNWWWNY^ 



Fig. 13. — Machine for making ozone 



S ozone 
and air 



edly noticeable by the odor is to dissolve about a half 
gram of potassium permanganate in about ten cubic 
centimeters of water and add cautiously two or three 
cubic centimeters of strong sulphuric acid. 

5. Practical Uses of Ozone. — In many of the cities of 
Europe, especially of France and Russia, ozone is used 
in purifying the water supplies, just as has been men- 
tioned chlorine is in America. It is said that one gram 
of ozone, which would be about one pint, is sufficient 



3 A " t; n -Toil — T 



OZOXE AND HYDROGEN DIOXIDE 69 

to destroy 30,000 pathogenic bacteria per cubic centi- 
meter in 250 gallons of water. To make this statement 
clear, let it be said that 250 gallons, roughly speaking, 
is 1,000 liters, which equal 1 million cubic centimeters. 
So, with 30,000 bacteria per cubic centimeter, one gram 
of ozone would have the power of destroying 30,000 
million bacteria, like those of cholera or typhoid. 
Ozone is also being used in many theatres and picture 
shows and similar places for the purpose of purifying 
the air. By the systems of ventilation it is pumped 
into the room along with the streams of fresh air. The- 
oretically the plan seems valuable but in practice there 
seems some doubt as to its efficacy. Ozone is also used 
in some large flour mills to destroy any traces of smut 
or must that may not have been removed by the proc- 
esses preliminary to milling. Fig. 13 illustrates one type 
of ozonizer used in obtaining the ozone used for the pur- 
poses just mentioned. The current of air enters at E 
and leaves at D; 5 is a glass tube lined on its inner 
surface with tin foil; A is a larger tube, also of glass, 
covered on its outer surface with the same metal; the 
binding posts of an induction coil are connected with 
these two tin foil coatings. The electric current spreads 
over the surface of one. and being of high voltage, 
passes through the space from A to B in a brush dis- 
charge so that practically all the enclosed air is sub- 
jected to the condensing effects of the electricity. 

Hydrogen Dioxide 

6. What Is Hydrogen Dioxide? — To the public, hy- 
drogen dioxide is sold in a diluted form of about 3 per 
cent under the name of Dioxygen, or Hydrogen Perox- 
ide. Thus diluted, it is not different from water in 



70 CHEMISTRY FOR NURSES 

appearance ; more concentrated, it is thicker and some- 
what sirupy. In composition it differs from water in 
that it contains twice as much oxygen. In the elec- 
trolysis of water it was found that the volume of hy- 
drogen obtained was twice that of the oxygen; were 
the same experiment possible with hydrogen dioxide 
the volumes of the two gases would be the same. 

7. Characteristics of Hydrogen Dioxide. — In the con- 
centrated form it is very unstable, the extra volume of 
oxygen being rapidly set free. In the diluted commer- 
cial forms this same process is going on but very slowly. 
It has a slight odor and a peculiar taste. It is strongly 
germicidal due to the oxidizing effects of the nascent 
oxygen being evolved at all times. 

8. Uses. — Being a mild germicide, yet at the same 
time effective, and perfectly safe even in the hands of 
the least skillful, it has wide application in this way. 
It is also an excellent bleaching agent for such animal 
products as hair, wool, silk, feathers and ivory and has 
extensive use for some of these. 

9. Test for Hydrogen Dioxide. — A few drops of di- 
oxygen if added to about ten cubic centimeters of 
starch mucilage or thin paste in a test tube together 
with a very little of potassium iodide solution gives the 
whole a beautiful deep blue color. The same test ap- 
plies for ozone except that a strip of white paper must 
be dipped in the starch-iodide solution and suspended 
in the atmosphere of ozone. The starch on the paper 
turns blue. 

Exercises for Review 

1. What is ozone? 

2. What is an allotrope? Name several. 

3. What relation in density between ozone and oxygen? 



OZONE AND HYDROGEN DIOXIDE 71 

4. Give two ways by which ozone is produced in nature. 

5. Give two methods of making ozone in the class room. 

6. What are the most striking characteristics of ozone? Com- 
pare it with ordinary oxygen. 

7. What three practical uses for ozone are suggested? State 
the efficacy in one of these uses. 

8. How is the ozone obtained for these commercial uses? 

9. Compare hydrogen dioxide and water in composition. 

10. Give four characteristics of hydrogen peroxide. 

11. What two important uses has hydrogen peroxide? For 
what is it a good bleaching agent? 

12. Give a good test for ozone and hydrogen dioxide with re- 
sults. 



CHAPTER VII 
COMMON SALT AND SODIUM 

Outline — 

1. Abundance of Salt. 

(a) Found in the Blood. 

(b) In the Ocean. 

(c) In Salt Lakes. 

(d) In Mineral Deposits. 

2. Methods of Obtaining. 

(a) Evaporating Water from Lakes and Sea. 

(b) Evaporating Brine from Deposits. 

(c) Mining Eock Salt. 

3. Characteristics of Salt. 

4. Uses of Salt. 

(a) As a Preservative. 

(b) In Food. 

(c) In Eefrigeration. 

(d) In Manufacturing Other Sodium Compounds. 

5. Composition of Salt. 

(a) Determined by Electrolysis. 

6. Discovery of Sodium. 

7. Its Manufacture. 

(a) Description of Apparatus. 

8. Properties of Sodium. 

(a) Chemical. 

(b) Physical. 

9. Uses of Sodium. 
Exercises for Keview. 

1. Abundance of Salt. — We have already studied 
two familiar substances, water and air. Another al- 
most as familiar to us is common table salt, known to 
the chemist by the name of sodium chloride. It is 

72 



COMMON SALT SODIUM 73 

found almost everywhere: in the dust particles in the 
air, in the blood, .8 of one per cent, in the ocean and 
salt lakes, in many mineral springs, in immense de- 
posits in the earth. If a Bunsen burner is lighted in a 
room which has just been swept, it will be noticed that 
the flame is yellow from the dust particles: this is due 
to the sodium chloride present, for sodium compounds 
always color a flame yellow as we saw when we were 
studying hydrogen. In the ocean the water is about 
2.8 per cent common salt — an amount estimated at over 
35,000 billion tons. Some one has calculated that if the 
ocean averaged 1,000 feet in depth everywhere, the 
common salt contained would in bulk equal 3,500,000 
cubic miles. As this is probably a low assumption as 
to average depth, the actual salt contained would if 
piled up in mountains surpass in size and grandeur 
some of the great chains of our western Kockies. De- 
posits of great thickness exist at various places; four 
states, New York, Michigan, Ohio, and Kansas, fur- 
nish about 90 per cent of that made in the United 
States. At one place in the last named state the de- 
posits are said to be 300 feet in thickness and of most 
excellent quality. Smaller amounts are produced by 
California, Utah, West Virginia, Louisiana, Oklahoma. 
Texas and Pennsylvania. In California are one or more 
lakes of considerable extent with a crust of nearly solid 
salt, somewhat impure, six or eight inches in thick- 
ness during the dry season of the year, upon which one 
can walk with perfect safety. These lakes appear like 
one in our northern climates frozen over at a very 
windy time with snow falling so that the surface is left 
very rough. 

2. Methods of Obtaining. — In Utah the water is pumped 
from Salt Lake into shallow pools some distance away and 



74 CHEMISTRY FOR NURSES 

evaporated by the sun. The quality of salt is perhaps not 
of the best but may be used in many ways. In California 
considerable salt is made from San Francisco Bay: the 
water is pumped into pools and evaporated. In some 
states a portion of the salt is mined as is coal ; most of 
this is put on the market in the form of rock salt either 
for use of cattle or crushed for refrigeration mixtures. 
In most of the salt-producing states, holes are drilled 
down into the salt layer, water is run down and allowed 
to stand until saturated and is then pumped out through 
an adjacent hole. This method gives a brine much 
more concentrated than that obtained from the ocean or 
bay; it is run into an evaporating pan and heated till 
one of the impurities, calcium sulphate, usually present, 
on account of its being less soluble, separates out, Then 
the solution is run into a second pan and the concen- 
tration continued. 

3. Characteristics of Common Salt. — In small quan- 
tities salt is not harmful ; in fact it is deemed necessary 
in the animal economy as furnishing the means of pro- 
viding the hydrochloric acid in the stomach. In large 
amounts it becomes even toxic in its action, and in 
China it is said that it is often used as a means of com- 
mitting suicide. Upon the lower organisms it is al- 
ways destructive and its preservative qualities depend 
upon this fact. Most people have the idea that table 
salt is hygroscopic, but magnesium chloride, an im- 
purity found in most salt deposits to an amount of 
nearly four-tenths of one per cent of the Avhole is the 
cause of the trouble. To prevent table salt from becom- 
ing damp in rainy weather some manufacturers mix 
with it a small amount of starch or prepared chalk or 
even cooking soda: this coats the salt grains contain- 
ing the impurity so that they can not take up the mois- 



COMMON SALT SODIUM 75 

ture from the air. Analysis of the various samples of 
table salt on the market show a content of sodium 
chloride ranging from 97 to 99 per cent. 

4. Uses of Salt. — The uses of salt are most too com- 
mon to need mention. A very considerable portion of 
that manufactured is used in the preservation of meats 
and meat products: in seasoning the food of the nation 
about eleven pounds per capita of table salt is used 
every year, while the total quantity employed in vari- 
ous ways reaches 30,000,000 barrels. Mixed with ice as 
a freezing mixture, salt is also used very extensively. 
It is also the starting point for several very valuable 
compounds, which will be studied elsewhere. 

5. Composition of Salt. — We have spoken of salt as 
sodium chloride. To prove this is not difficult. One 
of the best methods is that of electrolysis as was used 
in the case of water. A U-shaped tube, as shown in 
Fig. 14, is filled with salt water to which has been added 
a few drops of a solution of phenolphthalein in 50 per 
cent alcohol. Electrodes are inserted, after determin- 
ing which way the current is flowing, and within a few 
seconds the solution at the negative pole is turned 
reddish violet in color, while if means be taken to col- 
lect the gas evolved there it will be found to be hy- 
drogen. Further experiment will show that sodium 
hydroxide has been formed in this tube and it was this 
which gave the color to the phenolphthalein. At the 
positive electrode a gas of very offensive irritating 
odor is given off which later will be shown to be 
chlorine. This experiment may now be repeated using 
a salt solution colored blue with litmus: no change 
will be apparent at the cathode, but at the anode where 
the chlorine is being produced the blue color is rapidly 



76 



CHEMISTRY FOR NURSES 



bleached. Again if the salt solution colored blue with 
litmus have a drop of hydrochloric added to make the 
solution red and the current then be passed, at the 
cathode where the sodium hydroxide is forming the 
solution becomes blue caused by the hydroxide, while 
the other arm is quickly bleached as before. The stu- 
dent will understand why the sodium is not apparent 
at the cathode as the chlorine is at the anode if he re- 
fers to the work in hydrogen. It will be remembered 
that sodium in contact with water rapidly decomposes 
it, setting free hydrogen. So here the sodium particles 
as fast as formed at the cathode attack the water, pro- 
ducing sodium hydroxide and hydrogen. 




Fig. 14. — Electrolysis of salt in water. 



6. Discovery of Sodium. — For some years previous 
to 1807- sodium hydroxide had been regarded as an ele- 
mentary substance. It was left to Sir Humphrey Davy 
to prove that it was a compound of sodium. By fus- 
ing the compound and passing a current of electricity 
through it he obtained the silvery metal at the cathode. 

7. Its Preparation. — At the present time sodium is 
manufactured by the same plan suggested by Davy. 
Changes have been made in the apparatus, as a com- 
mercial plant must always differ from a laboratory 
model, but the principle is the same. Fig. 15, illus- 
trating what is now known as the Castner process, will 



COMMON SALT SODIUM 



77 



show the method. A large metal vessel usually of iron, 
marked V in figure, contains the caustic soda to be 
melted; through the bottom of this is inserted a bundle 
of carbon rods which serve as the cathode; another 
vessel, W f which forms the anode, is inverted over the 
larger one and dipping into the melted caustic ; in the 
center, over the cathode, is a collecting pot, P, closed 
at the bottom by a coarse wire gauze which readily per- 
mits the passage of the melted caustic. When the soda 
has been melted by the application of heat the cur- 
rent is switched on; oxygen collects on the anode and 
bubbles out ; sodium and hydrogen, both being posi- 
tive, collect on the carbon rods and rise into the col- 




Fig. 15. — Preparation of sodium. 



lecting pot. The hydrogen is allowed to escape and 
when somewhat cooled the sodium is dipped out and 
poured into moulds. 

8. Properties of Sodium. — As already stated after 
potassium, sodium is the most electropositive of all the 
metals. It is silver white in color, almost as soft as 
putty, melts at 95.6° C, has a specific gravity of 0.97, 
which means it is just a little lighter than water; 
heated somewhat, it burns in chlorine, producing com- 
mon salt; likewise it will burn in oxygen or the air, 
forming sodium peroxide, corresponding to hydrogen 
peroxide, which has been mentioned elsewhere under 



78 CHEMISTRY FOR NURSES 

the name of "oxone;" it reacts vigorously with cold 
water, violently on hot, with the formation of hydrogen 
and sodium hydroxide. Naturally, therefore, in the 
air, always more or less moist, it is rapidly tarnished; 
first sodium hydroxide is formed and later, by the ab- 
sorption of the carbon dioxide, sodium carbonate. In 
the laboratory it is kept in bottles covered with some 
oil containing no oxygen, like benzine or kerosene. On 
wet blotting paper, not being able to roll around as on 
water, it quickly melts, and if dropped to the floor as 
it is about to. catch fire, it bursts into many small glob- 
ules, burning with a yellow flame as they roll off in 
every direction. 

9. Uses of Sodium. — In the chemical laboratory there 
are a number of uses for' sodium ; also for the manufac- 
ture of a variety of complicated organic compounds, 
like artificial rubber; but its characteristics do not ad- 
mit of any extensive general uses. 

Exercises for Review 

1. What can you say of the distribution of salt upon the earth? 

2. Name the best salt-producing states. 

3. From what sources is salt obtained in various locations of 
the United States? 

4. Give three ways of obtaining salt. Which is the more com- 
mon ? 

5. Of what value is salt in the human economy? 

6. What causes table salt to become damp? How is this some- 
times prevented? 

• 7. Name some valuable uses for salt. 

8. What is the composition of salt? Give method of proof. 

9. Who was the discoverer of sodium? How was it made? 

10. Describe process of manufacturing sodium now. 

11. Describe sodium. 

12. How is sodium kept in the laboratory? 

13. What uses has sodium? 



CHAPTER VIII 

CHLORINE AND THE HALOGEN FAMILY 

Outline — 

1. Names of the Halogens. 

(b) General Characteristics. 

2. Historical Points of Chlorine. 

(a) Discoverer and His Ideas of Chlorine. 

(b) His Name for It; Reasons. 

(c) Humphrey's Work and Name Suggested. 

3. Preparation of Chlorine. 

(a) In Laboratory. 

(b) Commercial Method. 

4. Description of Chlorine. 

(a) General. 

(b) Combustion Experiments. 

(c) Physiologic Effects. 

(d) Gas Masks. 

5. Uses of Chlorine. 

(a) For Bleaching. 

(b) Sterilizing Water Supplies. 

(c) In the Sick Room. 

(d) In Gas Warfare. 
C. Hydrogen Chloride. 

(a) Historical. 

(b) Method of Preparing. 

(c) Description of. 

7. Hydrochloric Acid. 

(a) Historical. 

(b) What it is. 

(c) Characteristics. 

(d) Value of. 

8. Aqua Regia, What? and Uses. 

79 



80 CHEMISTRY FOR NURSES 

9. Iodine. 

(a) Discovery. 

(b) Sources of Supply. 

(c) Preparation and Purification. 

(d) Description of. 

(e) Uses. 
Exercises for Eeview. 

1. The Halogens. — The word halogen means salt pro- 
ducer. It is given to a group of four elements the gen- 
eral characteristics of which are very similar and which 
form a large number of compounds closely resembling 
common salt. They are fluorine, chlorine, bromine and 
iodine with atomic weights respectively of 19; 35.46; 
78.92 ; and 126.92. The first two are gases, the third a 
liquid and the fourth a solid. They all have an irri- 
tating odor, somewhat similar, but differing in inten- 
sity, that of iodine being feeble. They all have great 
chemical activity, but in the inverse order of their 
atomic weights, fluorine being very much more active 
than iodine. In the present chapter Ave shall study 
only the chlorine and iodine. 

2. Some Historical Facts of Chlorine. — Chlorine was 
discovered by Scheele in 1774; it will be remembered 
that the year previous he prepared oxygen from 
manganese dioxide. Chlorine he obtained from the 
same oxide by treating it with strong hydrochloric acid 
in which experiment he thought the oxygen contained 
in the manganese dioxide had combined with the acid. 
Therefore, in the terms used in his day he named it 
dephlogisticaied marine acid air, which in our day 
would mean oxidized hydrochloric acid gas. So Scheele 
did not know he had discovered a new element in 
chlorine, and his idea was shared by other chemists for 
considerably over a quarter of a century, until Sir 



CHLORINE AND THE HALOGEN FAMILY 



81 



Humphrey Davy proved it to be an element and sug- 
gested the name it now has. 

3. Methods of Obtaining Chlorine. — The usual plan 
in the laboratory is that used by Scheele, and a con- 
venient form of apparatus for use is shown in Fig. 16. 
The manganese dioxide is put into the flask, the cork 
and thistle tube inserted and when everything is ready. 
the hydrochloric acid is added. The method of col- 




Fig. 16. — Preparation of chlorine in the laboratory. 

lecting the gas is called doivnward displacement and is 
the one commonly used when a gas is heavier than air 
and soluble in water. 

Commercial Methods of Manufacture. — Several pat- 
ents have been taken out for preparing chlorine on a 
large scale by the electrolysis of a saturated solution 
of common salt. In the preceding, chapter in studying 
the composition of salt we have seen a laboratory plan 
of making the experiment; the commercial apparatus 
seeks to keep separate the products formed and use all 



82 



CHEMISTRY FOR NURSES 



of them, in order to cheapen the process. One type of 
these machines is shown in Fig. 17. The bundle of car- 
bon rods in the central compartment which contains 
water serves as the cathode ; an anode is inserted into 
each of the other compartments, which contain the sat- 
urated brine ; a layer of mercury covers the bottom 
and serves as a seal between the two outer and the cen- 
tral compartments. The chlorine is set free at the 
anodes and is drawn off there; the sodium on being 
repelled toward the cathode meets the mercury and dis- 
solves in it. By means of an eccentric, E in figure, the 
trough is continually rocked so that the mercury con- 
taining the sodium comes into contact with the water 




-Q- 



77T 



Fig. 17. — Manufacture of chlorine. 

in the central compartment where the usual effect takes 
place with the formation of sodium hydroxide and the 
evolution of hydrogen. It will be seen therefore that 
by this process three products are obtained at the same 
time. 

4. Characteristics of Chlorine. — The term chlorine is 
from a Greek adjective meaning green and was sug- 
gested for this gas because of its greenish yellow color. 
It is about two and a half times as heavy as air, will 
not burn in the air, but in it a large number of sub- 
stances will burn, most of them taking fire spontane- 
ously. Nearly all the metals, if finely powdered and 
sifted into chlorine, burn with a shower of sparks. 



CHLORINE AND THE HALOGEN FAMILY 83 

Several other metals, malleable in character, if rolled 
into thin foil and lowered into a bottle of chlorine take 
fire the same way. Sodium must be heated, but when 
this is done it burns in chlorine producing a white 
solid which is common salt. Phosphorus lowered into 
chlorine is ignited almost instantly ; turpentine, heated 
to near its boiling point, and placed in chlorine on a 
strip of blotting paper burns with a copious volume of 
dense, black smoke and a dull red flame which disap- 
pears when all the turpentine has been decomposed. 
The paper does not catch fire as its kindling tempera- 
ture is above that of the burning hydrogen; and really 
it is only the hydrogen that is combining rapidly with 
the chlorine while the other constituent of turpentine, 
carbon, is set free to form the dense clouds of black 
smoke. From these experiments we see that combus- 
tion may take place in the absence of oxygen and with 
other substances. We must, therefore, broaden our 
ideas regarding it and define it as the union of any 
two substances with such rapidity as to produce heat 
and light. A burning jet of hydrogen inserted into a 
bottle of chlorine continues to burn as well as in the 
air; in reality it burns with much more vigor. 

At ordinary room temperature chlorine will liquefy 
under seven atmospheres' pressure; or, at -33° C. it 
becomes a liquid at one atmosphere pressure. In the 
liquid form it is of a beautiful golden yellow color, and 
may be kept in a strong glass tube hermetically sealed. 
At lower temperatures it becomes a white solid, re- 
sembling snow, which changes to yellow as it melts. 
It is soluble in Avater, two volumes to one, hence can 
not be collected over water without considerable loss 
of gas. It has a very irritating odor, attacks the throat. 



84 CHEMISTRY FOR NURSES 

bronchi and lungs, and if much is inhaled causes in- 
tense suffering and ultimately death. There is no 
known satisfactory antidote: ammonia mixed with air 
or the fumes of alcohol if inhaled afford some relief. 
The gas mask used by the soldiers in case of gas at- 
tacks owes its efficiency to the use of sodium thiosul- 
phate or to a very porous charcoal made from nut shells 
or both, through which the air must pass before being 
inhaled. These substances absorb and retain the 
chlorine so that it does not reach the individual. 

5. Uses of Chlorine. — One of the most extensive uses 
of chlorine is for bleaching. Practically all cotton and 
linen goods are bleached by this means, also much of 
the paper pulp for white paper. Many of the larger 
flour mills throughout the middle west and possibly 
elsewhere treat the flour with chlorine to render it 
whiter than it would be otherwise. It is also used in 
all large steam laundries to impart the excessive 
whiteness now demanded by a too critical public: the 
result is a much shortened life of all white goods sent 
to the laundry. 

By experiment it will be found that chlorine does 
not bleach any substance if perfectly dry. Moisture 
must be present, The explanation is that chlorine does 
not do the work directly, but when brought into con- 
tact with water a reaction takes place, forming hydro- 
chloric and hypochlorous acids. The latter compound 
is very unstable and rapidly breaks up setting free 
oxygen. It is this nascent or atomic oxygen that does 
the work. It will be seen, therefore, that the process 
is really one of oxidation. That oxygen is really set 
free can be shown by a very simple experiment, illus- 
trated in Fig. 18. The test tube shown is entirely, and 
the evaporating dish partly, filled with water which has 



CHLORINE AND THE HALOGEN FAMILY 85 

been saturated with chlorine in a room not very light. 
It is then placed in a window in bright sunlight, where- 
upon bubbles of gas will be seen collecting in the upper 
part of the tube. If tested with a pine splinter in the 
usual way it will be found to be oxygen. 

As previously stated chlorine either in the liquid 
form or as a calcium compound is used in the steriliz- 
ing of city water supplies. It is a powerful disinfec- 
tant. The compound of chlorine and lime known as 
bleaching powder, is valuable in sick rooms. A spoon- 
ful or two in a saucer of water gives off slowly free 
chlorine: the quantity is not sufficiently great to be 




Fig. 18. — Effect of sunlight on chlorine water. 

noticeable except close to the dish yet it has a very 
beneficial effect upon the air. Moreover, it is very 
cheap, and is sold commonly under the name, chloride 
of lime. Chlorine is also extensively used in the ex- 
traction of gold from its ores. 

It may be said, further, that chlorine was the first 
of the poisonous gases to be used in warfare. Steel 
cylinders, containing liquid chlorine, the wind blowing 
toward the English and French troops and the ground 
sloping in the same direction, were opened: the pres- 
sure being relieved, the liquid was with very great ra- 
pidity converted into a gas and flowed down hill in great 



86 CHEMISTRY FOR NURSES 

greenish-colored waves. Later gas bombs and various 
other devices as well as other poisonous gases were 
used. 

6. Hydrogen Chloride. — Under the name, spirit of 
salt, and later, marine acid air, this compound has been 
known to the chemist for several hundred years, pos- 
sibly since the middle of the fourteenth century. The 
easiest way of obtaining it is to treat common salt with 
strong sulphuric acid and heat gently. 

Characteristics of Hydrogen Chloride. — It is a color- 
less gas, of very irritating odor, heavier than air, will 
not burn or cause other substances to burn. In 
solubility it ranks next to the highest of the common 
gases: one liter of ice cold water will dissolve 600 liters 
of hydrogen chloride. Putting this in other words, a 
liter being about a quart, and 600 quarts being 150 
gallons or three large barrels, one quart of ice water 
will dissolve three of our largest sized barrels of the 
gas under one atmosphere of pressure. If the breath 
is blown across the top of a tube or flask generating 
hydrogen chloride, copious white fumes are seen ; the 
explanation is that the moisture has been removed 
from the breath by the gas and has been condensed 
as tiny drops, just as is the case in a fog. At -80° C. 
it becomes a colorless liquid, like water, which has lit- 
tle or no effect upon metals as long as no water is 
present. 

7. Hydrochloric Acid. — Hydrochloric acid is a so- 
lution of hydrogen chloride in water. At 20° C, 
which is about the ordinary temperature of a room 5 
a liter of water will absorb about 450 liters of hy- 
drogen chloride and give a solution containing about 
36 per cent of the gas. This is sold as strong hydro- 



CHLORINE AND THE HALOGEN FAMILY 87 

chloric acid. The term muriatic, is more often ap- 
plied to the impure variety, yellow in color, due to 
the presence of small quantities of iron chloride, and 
other impurities. If strong hydrochloric acid is boiled. 
it constantly becomes weaker until the solution con- 
tains 20 per cent of the gas after which it remains con- 
stant. If a weak solution is boiled, the water evap- 
orates the faster until a strength of 20 per cent is at- 
tained. 

Uses of Hydrochloric Acid. — A century ago hydrogen 
chloride was a waste product from the sodium carbon- 
ate factories of England and France. Being heavier 
than air, and soluble in water, tall chimneys made to 
carry it away, were of little avail. In the absence of 
wind it settled to the ground, rendered the air irre- 
spirable, and killed vegetation all about the factories. 
Brought down by rain it attacked all tools and most 
metal objects exposed. Attempts were made to carry 
it away in streams, but here it killed the fish and other 
aquatic animals. Finally, stringent laws compelled the 
manufacturers to seek the aid of. chemists in devising 
uses for a worse than troublesome gas. So successful 
were their efforts that in solution now hydrogen chlo- 
ride is one of the most valuable and most extensively 
used of any of the acids. In fact, wherever the old 
method of making sodium carbonate is still followed it is 
solely for the purpose of the acid obtained, while the soda 
crystals have become the by-product. There is scarcely 
any factory or industry which does not use more or less 
hydrochloric acid. In the stomach, it has already been 
mentioned, hydrochloric acid plays an important part 
in digestion. The reason some animals can so readily 
digest bones which they imperfectly masticate and 



88 CHEMISTRY FOR NURSES 

swallow is that their digestive fluids contain a large 
amount of hydrochloric acid which readily dissolves 
the mineral matter from the bones and then the animal 
portions are digested about as so much gelatin would be. 

8. Aqua Regia. — The words "aqua regia" mean 
royal water and are applied to a mixture of hydro- 
chloric acid with nitric in the proportions of three of 
the former to one of the latter. They are so used 
because the mixture is an excellent solvent for gold and 
for a considerable time was the only good solvent 
known for the king of metals. The solvent power is 
due to the evolution of chlorine. This chlorine, as is 
the case with the oxygen from hydrogen peroxide, 
ozone, or in bleaching by chlorine, is in the nascent or 
atomic state, and is exceptionally active. The reason 
for this can be seen if it be remembered that unlike 
elements unite chemically. However, if no element 
positive in character is present for union with the chlor- 
ine atom, it, being unable to exist alone, combines with 
another chlorine atom and forms the molecule. Aqua 
regia is also the best solvent for platinum as well as 
some other metals. It always produces a chloride when 
it dissolves a metal. This would necessarily be so if it 
is the chlorine which does the work. 

9. Iodine. — This halogen was discovered by Courtois 
in 1811. In heating the ashes of sea weeds he noticed 
a beautiful violet vapor which was found to be the 
gaseous form of an element hitherto unknown. It re- 
received its name from a Greek word meaning violet. 

Source of Supply. — For a good many years all the 
iodine used was obtained from kelp, a species of sea 
weed; but at the present time most of the supply comes 
from the saltpeter beds of Chile where it exists as 



CHLORINE AND THE HALOGEN FAMILY 



89 



sodium iodate, mixed in very small amounts with the 
sodium nitrate. 

Preparation and Purification. — If chlorine is bubbled 
into a solution of an iodine compound, as sodium iodide, 
the chlorine, being more electronegative, combines 
with the sodium and releases the iodine. This is shown 
by the solution assuming the color of iodine tincture. 
From this it may easily be distilled out and collected 
in a suitable condenser ; this is the method employed 
in France for the preparation of iodine, whether from 




Fig. 19. — Iodine apparatus. 

seaweed ashes or other source. Another method, that 
of treating the iodine compound with manganese diox- 
ide, and sulphuric acid and distilling out the iodine, 
is more often employed in Great Britain. By any 
method certain impurities are present which are re- 
moved by sublimation. This means the distillation of 
a solid which does not melt on heating, but changes 
directly into vapor. The process will be understood 
from Fig. 19. Each conical shaped condenser receives 
the sublimate from the preceding. 

Characteristics. — Iodine is a crystalline solid, lustrous 



90 CHEMISTRY FOR NURSES 

as a metal, nearly black in color, which gives off vapors 
even at ordinary temperature, violet in color. It has an 
odor resembling chlorine but much weaker and less 
irritating. It combines with many of the metals read- 
ily. A crystal of iodine laid upon a thin slice of yel- 
low phosphorus reacts with it vigorously with suffi- 
cient heat produced to set the phosphorus on fire in a 
few seconds. It is but slightly soluble in cold water, 
a little more so in hot, while in a solution of potassium 
iodide in water it dissolves readily. Alcohol, chloro- 
form, carbon disulphide and ether are all fine solvents. 
With starch paste or mucilage, a dilute solution of 
iodine gives a beautiful blue color. This is the usual 
test for it and is a very delicate one, one part of iodine 
being perceptible in several hundred thousand of water. 
Uses of Iodine. — The main use of iodine is for med- 
icine in the form of tincture, which is an alcoholic so- 
lution. This is used as a counterirritant in case of 
swellings, inflammation, etc., also as an antiseptic in 
surgical operations, accidental wounds, and the like. 
It is stronger and more penetrating than hydrogen 
peroxide hence sometimes preferable, but it is also more 
severe. In iodoform, a light yellow solid of rather 
peculiar and disagreeable odor, it is also often used as 
an antiseptic. An extract from the thyroid body of 
sheep, known as iodothyrin, is given medicinally as a 
stimulant to the development of the same organ in the 
human body. 

Exercises for Review 

1. Name the halogens and state how they received the name. 

2. Give their more common characteristics. 

3. Who discovered chlorine? What was his idea about it? 



CHLORIXE AND THE HALOGEX FAMILY 91 

4. Who proved it to be an element ? Why did he name it 
chlorine ? 

5. What is the usual way of preparing and collecting chlorine? 

6. Describe briefly a commercial method of making chlorine. 

7. Give the effects of chlorine upon several metals and other 
substances. 

8. How does it compare with oxygen in chemical activity? 

9. What is the effect if inhaled? Antidotes? 

10. Explain how the gas mask prevents injury. 

11. Xame four kinds of substances bleached commercially by 
chlorine. 

12. Explain how chlorine bleaches. What other agent have we 
studied which bleaches the same way ? 

13. Give some medical use for chlorine; also two other impor- 
tant uses. 

14. Mention two old names for hydrogen chloride. Why so 
named ? 

15. How is it prepared? 

16. What are the chief characteristics of hydrogen chloride? 

17. Illustrate its great solubility. 

18. What is hydrochloric acid? Muriatic acid? 

19. Mention some of the annoyances of hydrochloric acid gas a 
century ago. 

20. What can you say of its value now? 

21. What is aqua regia ? It uses? Why does it make chlor- 
ides always? 

22. When, by whom, and how was iodine discovered? 

23. Give two sources of our commercial supply of iodine. 

24. What two ways of preparing iodine can you mention? 

25. What is sublimation? How different from distillation? 

26. Describe iodine. What are the best solvents? 

27. What is tincture of iodine? Its uses? 

28. What is iodoform, iodothyrin ? Their uses? 



CHAPTER IX 

GASES AND SOME GAS LAWS 

Outline — 

1. States of Matter. 

2. Effects of Heat on Matter. 

(a) On Solids and Liquids. ' 

(b) On Gases. 

3. Charles' Law. 

(a) Statement and Illustrations. 

(b) Absolute Zero. 

4. Correction of Gas Volumes for Temperature Changes. 

(a) Standard Temperature. 

(b) Working Formula. 

5. Effect of Pressure upon Gases. 

6. Boyle's Law. 

(a) Statement of. 

(b) Demonstration of. 

(c) Formula for Pressure Corrections. 

7. Pressure Headings. 

(a) How Taken. 

(b) Aneroid Barometer. 

8. Temperature and Pressure Corrections. 

9. Practical Applications of These Gas Laws. 

10. Deductions from These Laws. 

(a) Matter Not Continuous. 

(b) Molecular Theory. 

(c) Gas Pressures Due to Molecular Motion. 

(d) Atomic Theory of Dalton. 

(e) Avogadro's Hypothesis. 

11. Atomic Weights. 
12'. Molecular Weights. 
Exercises for Eeview. 

92 






GASES AND SOME GAS LAWS 93 

1. States of Matter. — All are familiar with, the fact 
that matter exists in three states, — solid, liquid and 
gaseous. Many substances exist in all three. Ice be- 
comes a liquid on the addition of heat, and at a still 
higher temperature changes into a gas. So do paraffin 
and a large number of other familiar substances. Oth- 
ers, however, before they reach a point at which they 
would melt, are decomposed into other and simpler 
compounds. 

2. Effects of Heat.— The first effect of heat upon 
practically all substances is that of expansion. This 
is true whether it be a gas, a liquid or a solid. In the 
case of liquids and solids, the rate of expansion is 
exceedingly variable, no two substances being exactly 
the same. Gases, on the contrary, behave alike, so that 
certain laws regarding them have been discovered 
which apply to all. 

3. Charles' Law. — When a volume of gas at 0° C. is 
heated it is found to expand % 73 of its volume for 
every degree heated. That is, if we had 273 c.c. of 
hydrogen or any other gas in a vessel at 0° C. and warmed 
it to 1° C. the volume would become 274 c.c. ; if we heated 
it ten degrees, the volume would be 283 c.c. ; if it were 
cooled ten degrees, the volume would be 263 c.c. In the 
briefest form these facts are stated in what is known as 
Charles ' Law i ' ' The volume of any gas, provided the pres- 
sure is constant, varies uniformly with the temperature. ' ' 
From what has been said in illustration, if the supposed 
volume of 273 c.c. were cooled to 100 degrees below 
zero it would decrease 100 c.c. ; if cooled 273 degrees 
would entirely disappear. It is unbelievable by any 
one that by removing heat from a body we could cause 
it to disappear or cease to exist. The truth is, that all 



94 



CHEMISTRY FOR NURSES 



substances liquefy or solidify before reaching any such 
temperature as -273° C, and thereafter the law does 
not apply to them, for the rate of expansion and con- 
traction of solids and liquids is exceedingly small as 
.compared with that of gases. The temperature of 
- 273 degrees of centigrade, however, is known as ab- 
solute zero, for reasons that will be explained later; 
and while no thermometer of this name is manufac- 
tured, it is often necessary to use the absolute scale. 



F C A 

' 00 fl 373 fl B^ty 'P oin t 



68 - 

32- 



293 
273 



mj 



Pi. 



mm® 

Fig. 20. — Comparison of thermometers. 

hence the comparison of it with the centigrade is shown 
in Fig. 20. The freezing point of water, zero centi- 
grade, is 273 absolute; boiling water, 100 C, is 373 
absolute, etc. 

4. Correction of Volume Readings. — Because of the 
great difficulty of weighing a gas, the quantity is usu- 
ally expressed in volume ; but as changes in tempera- 
ture cause such great variation in volume, some tem- 
perature must be taken as a standard to which all vol- 



GASES AND SOME GAS LAWS 95 

umes are referred. The freezing point of water, being 
easy to determine, the centigrade zero, has been 
adopted and is often spoken of as the standard tem- 
perature. Suppose we have 500 c.c. of oxygen in a 
tank at 20° C. and wish to know its volume at 30°. 
According to Charles ' Law it would increase 1 % 7 a of 
the volume it occupied at 0° C, but we only know its 
volume at 20°. We make use of this proportion in all 
such cases: 

V: V ::T : T' 

or, what is more convenient, the equation derived from 
the proportion, 

VT' = V'T 

in which V is the original volume, V the new volume, 
and t and t' the original and new temperatures 
centigrade, respectively. Substituting in this equation 
we have, 

500 x (273 + 30) = V x (273 + 20) 

If t = temperature centigrade, and T, absolute, 

T = 273 + t. 

It will be noticed that we have used absolute thermom- 
eter readings, which must always be done in making 
corrections for temperature changes. Keeping this in 
mind, Charles ' Law is more accurately stated thus: 
"The volume of a gas, pressure remaining constant, va- 
ries directly as the absolute temperature.' ' By solving 
the above equation the value of V' will be the true 
volume of the gas at the new temperature. 

5. Effect of Pressure upon G-ase's.— It was thought 
for many years that liquids and solids could not be 
compressed: it is known now that they may be, though 



96 CHEMISTRY FOR NURSES 

but slightly. Furthermore, in undergoing pressure as 
was the case in heating them they are variable and 
obey no law. Gases, however, as on heating, behave 
alike, a fact discovered by Robert Boyle, already 
spoken of as the father of Physics and Chemistry. 

6. Boyle's Law. — Briefly stated, this law is, "The 
volume of any gas, temperature remaining constant, 
varies inversely as the pressure." This means that if 
we have 500 c.c. or any other volume of gas in a closed 
vessel to which we can apply pressure, and then double 
the original pressure the gas will be reduced to half its 
original volume. Likewise if we removed half the 
pressure the gas w T ould double in volume. This may be 
shown in what is known as a Boyle's Law apparatus, 
shown in Fig. 21. The short end of the tube is closed 
and enough mercury poured in to fill the bend as shown. 
As the mercury level is the same in both arms, the 
pressure upon the two surfaces must be the same. 
•Upon the open end the weight of the air is resting, 
hence there must be one atmosphere's pressure upon 
each surface. Now pour into the open end more mer- 
cury, sufficient to double the original pressure. The 
volume of the gas in the closed space is decreased to 
half what it occupied at the beginning. As the at- 
mospheric pressure varies greatly from day to day, so 
the volume of any gas will vary; it is often necessary, 
therefore, to make correction for pressure as was done 
for temperature changes. For such purposes, Boyle's 
Law is expressed in the form of a proportion: 

V: V ::P' :P 

in which V and V are the original and new volumes, 
respectively, and P and P' the corresponding pressures. 



GASES AND SOME GAS LAWS 



97 



Fig. 21. — Boyle's Law Apparatus. 



CHEMISTRY FOR NURSES 



For solving problems the proportion is better used in 
the form of an equation, thus: 



VP 



VP' 






7. Barometer Readings. — Probably all are familiar 
with the fact that atmospheric pressures are obtained 
by the barometer ; but these readings are usually given 




Fig. 22. — Aneroid barometer. 

in inches or millimeters and not in weight. We say that 
the barometric pressure was 29 inches when we mean 
that the pressure was equal to the weight of a certain 
column of mercury 29 inches high. But we destroy 
no mathematical relation when Ave substitute inches for 
weight and we save the calculation each time of the 



GASES AND SOME GAS LAWS 99 

weight of that much mercury. In scientific calculations 
millimeters are commonly used instead of inches, 760 
millimeters being the equivalent of 30 inches. On ac- 
count of convenience in handling, an aneroid barometer, 
shown in Fig. 22, is often used instead of a mercurial, 
and gives corresponding readings. Let us illustrate by 
a problem. Suppose we have 500 c.c. of gas at 760 mm 
pressure and desire to know the volume at 740 mm. 
Substituting in 

YP =Y'P' 

we have 

500 x 760 = Y' x 740 

from which the new volume is easily found. 

8. Temperature and Pressure Corrections. — In the 

discussion of Charles' and Boyle's Laws above, each 
was said to be true when the third factor is constant. 
That is, the volume varies directly as the absolute tem- 
perature if the pressure does not change; and the vol- 
ume varies inversely as the pressure provided the 
temperature does not change. Usually, however, both 
pressure and temperature vary. For such cases a com- 
bined formula is used, 

VPT' = Y'P'T 

in which the letters mean as in the preceding cases. 
Let us apply it in a problem. Suppose we want to 
know what the volume of 1,000 cu. ft. of natural gas 
measured at 20° C. and 750 mm. pressure, would be at 
30° C. and 720 mm. pressure. Substituting in the 
formula. 



100 



1,000 x 750 x (273 + 30) = V x 720 x (273 + 20) 

from which, the value of V is easily found. 

9. Practical Value of These Laws. — There are many 
ways in which these laws find practical application in 
modern life. The balloonist must take them into con- 
sideration when he fills his bag. If he puts too much 
gas in, when he ascends into a clearer and dryer air, 
the heat of midday may tend to produce such expan- 
sion of the gas contained as to burst the bag. If he 
puts in too little, the contraction upon cooling after 
dark may be sufficient to bring the balloon to the earth. 
Again in every city these laws apply in the case of the 
gas used for fuel and lighting. Most city ordinances 
specify that the gas shall be furnished at a pressure 
not under that of a certain number of inches of water 
pressure, say six or eight: now, if the gas company 
pumps gas through the mains at a pressure less than 
that specified, according to Boyle's Law, the volume 
would be increased, but there would be no more heat 
units in the greater volume at 4 inches pressure than in 
the smaller volume at 8 inches pressure: yet the meter 
would charge up the larger amount. It is obvious that 
gas should be sold not by volume but by number of heat 
units contained. 

10. Deductions from These Laws. — When a given vol- 
ume of gas is compressed, its weight remains constant; 
likewise, cooling or heating a gas does not change its 
weight. By modern apparatus it is possible to apply 
to a gas a pressure of 10,000 atmospheres whereby it 
is reduced to %o,ooo °^ the volume it originally pos- 
sessed. There is only one conclusion that can be reached 
from such facts and that is that gases are not made up 
of continuous matter but of separate particles which 



GASES AND SOME GAS LAWS 



101 



may be crowded much closer together. And as all gases 
behave alike under the same changes in conditions, this 
must be true of all gases. AVhile we are here consid- 
ering only gases, it might be interesting to inquire 
whether the same is true of liquids and solids. If 500 
c.c. of alcohol and a like volume of water are poured 
together in a graduated cylinder at first without mix- 
ing as shown in Fig. 23, and are then thoroughly stirred, 
it will be found that the volume is no longer 1000 c.c, 



Before mixmf A-fier mixing 




Fig. 23. — Contraction of volume on mixing two liquids. 

but about 900 c.c. If a certain weight of salt is dis- 
solved in 100 c.c. of water, it will be found that the 
new volume is but slightly above 100 c.c, and not nearly 
that of the water and salt originally. Into a liter of 
ice water we may pass several hundred liters of a 
hydrogen chloride gas before the water becomes satu- 
rated, and the gas all disappears without very greatly 
increasing the volume. Years ago attempts were made 
to compress water and other liquids in metallic globes 
and it was found that invariably upon flattening the 



102 CHEMISTRY FOR NURSES 

globe and thereby reducing the volume, the liquid was 
forced through the metal and appeared in tiny drop} 
upon the outside. A few years ago an Englishman, Sir 
Roberts-Austen, placed some cylinders of lead upon 
sheets of gold and allowed them to remain for four 
years. At the end of that time he found by testing the 
lead that there were gold particles in it as far up as 
eight millimeters. These and many other experiments 
all tend to show that liquids and solids as well as gases 
consist of matter not absolutely continuous. 

The Molecular. Theory. — All scientists now accept the 
theory suggested above, that matter is not continuous, 
but is made up of minute particles which they call 
molecules. The word, derived from the Latin, means 
a small mass. In solids these molecules are close to- 
gether; in liquids, somewhat farther apart, while in 
gases they are at very great distances relatively. For 
instance, the average distance of one molecule from 
another in a gas at ordinary temperature and pressure 
is vastly greater than that of the earth from the moon 
in proportion to the diameters of the bodies considered. 
For example, the diameter of the earth is about 8,000 
miles; the moon is distant from the earth about 240,000 
miles or about thirty times the diameter of the earth. 
A more accurate comparison would be that of the va 
rious planets of the solar system from each other and 
from the sun. A bottle "full" of hydrogen might be 
spoken of as a vacuum with a "few" -particles or mole- 
cules of hydrogen in it at relatively great distances 
from each other. So, when we compress a gas 10,000 
times, we have not merely moved the moon up to the 
earth, a distance 30 times the diameter of the earth, but 
10,000 times that distance, or relatively, 10,000x8,000 



GASES AND SOME GAS LAWS 103 

which is 80,000,000 miles, a distance nearly that of the 
earth from the sun. 

In solids, Lord Kelvin has shown conclusively, the 
distance from the center of one molecule to that of the 
next one is not less than % 00 millionth of an inch and 
not more than % 50 millionth of an inch. Cubing 500 
millions would give the possible number of molecules 
in a cubic inch, or cubing 250 millions, the least number 
there could be. Some one has estimated that to count 
the molecules lying in a row one inch long at the rate 
of one per second would require 23 years of 300 days 
each and ten hours a day ! 

Molecules in Motion. — Not only is matter composed 
of molecules but these tiny masses are at all times in 
motion. There is much evidence of this. Dust parti- 
cles, no matter how small, have no inherent power of 
motion and sooner or later all settle. Not so molecules: 
regardless of how little gas there may be in any closed 
space it is always evenly distributed and gives the 
same pressure at all points. Gases are also capable of 
indefinite expansion: if half the gas in a receiver be 
removed by an air pump, the remainder expands till 
it occupies the whole space ; and this continues indef- 
initely. In the study of the air Ave have already spoken 
of diffusion. It can be explained in no other way and 
means nothing else than that the molecules of the vari- 
ous gases constituting the air are in constant motion. 

Gas Pressures. — It is the constant bombardment of the 
molecules of a gas in a closed space that produces the 
pressure; if half the gas has been removed by means of 
an air pump the manometer will show only half the 
pressure that it elid at the beginning. This is because 
there are only half as many molecules now to bombard 
a given area as at first anel the pressure is correspond 



104 CHEMISTRY FOR NURSES 

ingly decreased. Likewise if we pump a gallon of air 
into a bicycle tire which already contained a gallon we 
have doubled the number of molecules ; there will be 
twice as many impacts per second now as formerly and 
the gauge will show double the pressure it did before. 

The Atomic Theory. — The theory that matter is com- 
posed of molecules satisfies most of the phenomena 
dealt with in the study of physics, but the chemist 
needs something more. John Dalton, who died in 1844, 
recognizing this fact, suggested what is now known as 
the atomic theory. Briefly stated it is this: molecules 
are composed of still smaller particles, called atoms, a 
word derived from the Greek, meaning not able to be 
divided-: second, that the atoms of each element have a 
certain, definite weight; third, that this weight is dif- 
ferent from that of every other element ; and fourth, 
that chemical union takes place between the atoms of 
elements and not between larger masses. Roughly put, 
this last statement means that nature furnishes us 
matter tied up in packages of different kinds having a 
certain definite weight, and when we unite them to 
form compounds, we must do so by using one package, 
or two, or more as may be needed. This hypothesis, 
offered so many years ago, seems to explain and be 
sufficient for all the laws of combination so far as it 
applies. 

Avogadro's Hypothesis. — In 1811, Avogadro, an 
Italian physicist, formulated the hypothesis which still 
bears his name. It is: " Equal volumes of all gases 
under the same conditions of temperature and pressure 
contain the same number of molecules.' ' No absolute, 
experimental proof can be offered, hence we do not often 
speak of it as a law; but it explains a large number of 



GASES AND SOME GAS LAWS 105 

observed facts not otherwise understood, is in viola- 
tion of none, and is undoubtedly true. 

11. Atomic Weights. — According to Dalton's atomic 
theory, the individual atoms have certain definite 
weights. Obviously, one atom is too small to be 
weighed, hence we can assign only relative values. As 
hydrogen is the lightest of all gases, seemingly, one 
atom of this element should be our unit. Accordingly 
the hydrogen atom was assumed to have a weight of 
one and to this unit weight was given the name 
microcrith ; and the weights of the other elements were 
compared to this; that is, oxygen being about sixteen 
times as heavy as hydrogen would have an atomic 
weight of 16, and so on for the other elements. It was 
found, however, that if the weight of the hydrogen 
atom was assumed as one microcrith, the comparative 
weights of a very large number of the other elements 
differed considerably from whole numbers, but if the 
hydrogen atom is assumed as weighing 1.008 micro- 
criths, oxygen then becomes exactly 16 and a very 
large number of the other elements have atomic 
weights either whole numbers or very nearly so. On 
account of the advantage this fact has in chemical cal- 
culations it has been accepted as preferable. The 
atomic weight of any element, therefore, is the weight 
of an atom of that element in microcriths, on the as- 
sumption that an atom of oxygen weighs 16 micro- 
criths or the hydrogen atom, 1.008 microcriths. 

12. Molecular Weights. — The molecular weight of a 
substance is the sum of the weights of the atoms con- 
stituting a molecule of that particular substance. 
Thus, we have found that water contains two parts hy- 
drogen to one of oxygen, by volume. Later it will be 



106 CHEMISTRY FOR NURSES 

shown that a molecule of water contains two atoms oi 
hydrogen and one of oxygen: adding the weight of two 
atoms of hydrogen to that of one atom of oxygen and 
omitting the decimals we have 18 as the molecular 
weight of water. The complete table of atomic weights 
of the elements will be found on page 283. 

Exercises for Review 

1. What three states of matter? How changed from one into 
another? Why do not all substances thus change? 

2. What is the primary effect of heat upon all substances? 
How are gases different from other substances? 

3. Give Charles' Law and illustrate. 

4. What is meant by absolute zero? What would 0°C. be on 
absolute scale? 20°C? 100°C? -23°C? -73°C? 

5. What is meant by standard temperature? 

6. A gas has a volume of 680 c.c. at 0°C. What would be its 
volume at 10°C? 

7. State Boyle's Law. Illustrate. 

8. What is meant when we say the pressure is 28 inches? 
What is the equivalent of 30 inches in millimeters? Keduce 
28.5 inches to millimeters. 

9. When temperature and pressure both change, what formula 
must be used? 

10. Give some practical application of these two laws. 

11. How do you explain the fact that a gas can be compressed 
so much, and a solid so little? Illustrate. 

12. Give some proofs that matter is not continuous in solids: 
in liquids. 

13. State briefly the molecular theory. Give some idea of 
the size of the molecule. 

14. What can you say as to the distance of gas molecules 
from each other? 

15. What proof can you give that molecules have motion? 

16. What is the cause of the pressure on the inside of an 
automobile tire? 



GASES AND SOME GAS LAWS 107 

17. If a tack pierces an automobile tire which showed on the 
gauge a pressure of 80 pounds and air escapes till the gauge only 
registers 20 pounds what part has escaped? 

18. State the points in Dalton's atomic theory. 

19. State Avogadro 's Hypothesis. 

20. What is meant by atomic weight? By a microcrith? 
Illustrate. 

21. What is meant by the molecular weight of a substance? 
Illustrate. 



CHAPTER X 

SYMBOLS AND FORMULAS 

Outline — 

1. Origin of Symbols. 

2. Symbols. 

(a) Consist of What? 

(b) Exact Meaning of. 

3. Formulas. 

(a) Consist of What? 

(b) Represent What? 

(c) Structural Formulas. 

4. Eadicals. 

(a) Consist of What? 

(b) Eepresent What? 

5. Chemical Equations. 

(a) Description of. 

(b) How Read. 

(c) Equality of. 
Exercises for Review. 

1. Origin of Symbols. — In olden days in order to 
render their notes unintelligible to any chance reader, 
the alchemists used many signs and hieroglyphics to 
represent their mixtures. Later it seemed highly de- 
sirable, that some brief method of representing ele- 
ments and compounds and the various chemical 
changes which took place should be adopted. Hence 
from an old practice with no system for its foundation 
has grown a method of symbolization, exact as any 
branch of mathematics, and valuable in the extreme in 
many ways, at the same time intelligible to every chem- 
ist the w^orld around. 

108 



SYMBOLS AND FORMULAS 109 

2. Symbols. — A symbol represents a single atom of 
an element. This is necessarily so as the atom is the 
unit in all chemical changes. The symbol of an element 
is its initial letter, or, as sometimes there are several 
elements beginning with the same letter, the initial 
letter and some other prominent letter in the word. In 
case two letters are used, the second is a small letter; 
the first is always a capital. It is important to remem- 
ber this as confusion may result otherwise. Thus, C 
represents carbon; 0, oxygen; Co, cobalt, a metal re- 
sembling iron ; CO, carbon monoxide ; a compound 
body. So, many other illustrations might be given 
where there would be room for doubt. Sometimes the 
Latin name is used as a derivation for the symbol: es- 
pecially is this true of those elements discovered and 
studied at a day when it was believed that the Latin 
language was the only one to endure for all time. 
Thus Ag is the symbol for silver, from argentum; Pb 
is for lead, from plumbum; An for gold, from aurum, 

3. Formulas. — As a symbol represents a single atom 
of an element, so a formula indicates a molecule of some 
substance. A formula is a combination of symbols and 
usually represents a molecule of a compound, though 
in its simplest form it may stand for a molecule of an 
element. Thus, H 2 which is a shortened form of HH 
is a combination of two symbols and represents a mole- 
cule of hydrogen: likewise, 000, written 3 , means a 
molecule of ozone and As 4 a molecule of arsenic, Gen- 
erally, however, the formula applies to a compound 
and shows not only what elements enter into the com- 
pound, but the amounts also. If more than one atom 
of an element is contained in a molecule of the com- 
pound that fact is indicated in the formula by placing 



110 CHEMISTRY FOR NURSES 

a small figure at the right and a little below the symbol 
for that particular element. Thus, H 2 S0 4 represents a 
molecule of sulphuric acid which contains 2 atoms of 
hydrogen, one of sulphur and four of oxygen. Again. 
•A1 2 (S0 4 ) 3 represents a molecule of aluminum sulphate, 
which contains two atoms of aluminum, three of sul- 
phur and twelve of oxygen, the figure 3 outside of the 
parenthesis multiplying everything enclosed therein. 
If it is desired to represent more than one molecule of 
a compound body, it is done by using a coefficient. 
Thus, 5H 2 S0 4 means five molecules of sulphuric acid. 
Obviously, and this is important to remember, the co- 
efficient multiplies each symbol in the formula. This 
is necessarily so, since, if there are four atoms of oxygen 
in one molecule of sulphuric acid, there would be five 
times as many in five molecules. The same would be 
true of the hydrogen and sulphur. 

Structural or Graphic Formulas. — Sometimes it is 
highly desirable to show the arrangement of the atoms 
in a molecule. Especially is this true in the study of 
carbon compounds where we may have two with the 
same empirical formula but with widely different prop- 
erties. Thus methyl ether and ethyl alcohol have the 
same empirical formula, C 2 H 6 0, usually written (CH 3 ) 2 
and C 2 H 5 OH, that they may be easily distinguished 
and to show that one is an oxide and the other a hy- 
droxide. Such compounds as these are said to be 
isomeric, from two Greek words meaning of equal parts. 
The two compounds are not at all alike in properties: 
the only way we can explain this is that the atoms are 
not linked together in the same manner. Structural 
formulas seek to make plain the method of linkage, 
thus : 



SYMBOLS AND FORMULAS 111 

H H 

I I 

Methvl Ether H— C— 0— C— H 

I I 

H H 

H H 

I I 
Ethvl Alcohol H— C— C— 0— H 

I | 
H H 

In sulphuric acid the atoms are linked thus: 

H— 

\ / 

S 

/ \ 

H— 

4. Radicals. — More often the term radical means a 
combination of symbols which represent a group of ele- 
ments forming a part of a compound, but which can 
not exist alone. Thus in all sulphates we find the group. 
S0 4 , but no such compound exists. We can prepare 
S0 2 and S0 3 , but not S0 4 . Moreover, such groups give 
individual tests as if they were single elements. Thus, 
any sulphate in solution would contain the group SO^ 
and will always give a white precipitate when barium 
chloride solution is added, just as sodium chloride or 
any other chloride in solution does with silver nitrate. 
A few of the more common radicals are NH 4 , found in 
all ammonium compounds, as NH 4 N0 3 , NH 4 C1; N0 3 in 
all nitrates, as KN0 3 ,NaN0 3 ; C0 3 , in all carbonates, as 
K 2 C0 3 , Na 2 C0 3 , CaC0 3 ; P0 4 in phosphates, K 3 P0 4 ; 
Xa 3 P0 4 ; C10 3 in all chlorates, KC10 3 ; HO, in hydroxides, 
as KHO, XaHO. Each one of these groups gives some 



112 CHEMISTRY FOR NURSES 

special test just as oxygen will ignite a glowing pine 
splinter. 

5. Equations. — The student is familiar with algebraic 
equations which are entirely abstract. In chemistry 
an equation means' much more. It is simply a short 
method of indicating the chemical change which has 
taken place in some experiment. The left-hand side 
indicates the substances used and the right hand, the 
products obtained. More than this, the exact amount 
of each is shown and as nothing can be lost, destroyed or 
gained in any chemical change, the sum of the amounts 
of the substances used must equal the sum of the weights 
of the substances obtained. However, as chemical 
change causes the destruction of a particular substance 
and the formation of new ones, the elements entering 
into the change will not be arranged as they were at 
the beginning. To illustrate: In studying water Ave 
passed a current of electricity through it and obtained 
two gases, hydrogen and oxygen, both of which we 
tested to be sure as to what they were, with the vol- 
ume of the former twice that of the latter. Expressing 
this chemical change in the form of an equation, we have 

Water (electrolyzed) yields Hydrogen 
(2 parts) and Oxygen (one part) 

Or, using symbols and formulas to make it briefer, 

H 2 -> H 2 + 

Now a molecule has been defined as the smallest por- 
tion of matter which can exist alone. It is known that 
a molecule of oxygen contains two atoms, hence in the 
equation just written we have shown a half molecule 
of oxygen which can not exist; hence it is customary 
to write this equation thus: 



SYMBOLS AND FORMULAS 113 

2H 2 -> 2H 2 + 2 

It will be noticed that the sign — > is used instead of the 
equality and is read yields or produces or in some sim- 
ilar way. Again, in studying hydrogen, we prepared 
the gas from water by the use of sodium. Thus, 

Sodium and Water produce Hy- 
drogen and Sodium Hydroxide. 

As must always be done we tested the products to know 
exactly what was obtained. To use symbols and for- 
mulas, this becomes, 

2Na + 2H 2 -> H 2 + 2NaHO 

and, Zinc and Sulphuric Acid give Hydrogen and Zinc 
Sulphate ; 



Zn + H 2 S0 4 -> H 2 + ZnSO 



■i 



If any of the equations given are studied, it will be 
observed that everything found upon the left side is 
also upon the right. Thus, in the sodium and water, 
the two parts of sodium of the left are found in the 
sodium hydroxide on the right: the four atoms of 
hydrogen in the water, on the right side are, two of 
them in the free molecule of hydrogen and the other 
two in the two molecules of sodium hydroxide, while 
the two atoms of oxygen in the water are found in 
the two of hydroxide on the right. Such is always 
the case. 

Exercises for Review 

1. Who were the first to use chemical symbols and what was 
their purpose? 

2. Of what does a symbol consist? What kind of letter or 
letters are used? 



114 CMEMISTtfcY FOR NUfeSEg 

3. Why is the observance of this last fact important! 

4. Give five symbols from the Latin. 

5. What is a formula? What does it represent? 

6. How is the number of atoms in a molecule expressed in a 
formula ? 

7. How many atoms of each element in alum, K Al o (SO ) 
24H O? 

8. Give exact amount of each in Na CO 10H O. 

2 3 2 

9. What is the usual meaning of the term radical? Illustrate 

10. Which of those given is positive? Which negative? Hov\ 
do you know? 

11. What does a chemical equation represent? Explain fully. 

12. Change the following into chemical formulas and symbols: 

a. Electrolysis of water. 

b. Burning hydrogen in the air. 

c. Exploding hydrogen in a pistol. 

d. Passing hydrogen over red-hot copper oxide. 

e. Exploding hydrogen in the eudiometer. 

f. Putting sodium on water. 

g. Heating mercuric oxide. 

h. Heating potassium chlorate. 

i. Heating potassium chlorate mixed with manganese di 

oxide, 
j. Burning charcoal in oxygen, 
k. Burning hydrogen in chlorine. 



CHAPTER XI 

OXIDES, ACIDS, BASES, AND SALTS 

Outline — 
1. Oxides. 

(a) Abundance of; What? 

(b) Classes of — Basic. Acidic. 

(c) Reaction of Each with Water. 
-. Bases and Alkalies. 

3. Anhydrides and Acids. 

4. Nomenclature of Bases. 

5. Nomenclature of Acids. 

6. Acids. 

(a) Physical State of. 

(b) Familiar Examples. 

7. Salts and Neutralization. 

(a) Classes of Salts. 

(b) Nomenclature of Salts. 

(c) Binary Salts. 
Exercises for Review. 

1. Oxides. — In the preceding chapters we have met 
with a number of oxides; from mercuric oxide Priestley 
prepared oxygen; Scheele made the same gas from 
manganese dioxide ; this same oxide was used as a 
catalyst in connection with potassium chlorate for mak- 
ing oxygen; it was used again with hydrochloric acid 
in making chlorine. When studying oxygen, various 
substances, as sulphur, charcoal, phosphorus and iron 
were burned in the gas; in each case an oxide of the cor- 
responding element was obtained. An oxide is a com- 
pound of two elements one of which is oxygen. As 

115 



116 CHEMISTRY FOR NURSES 

oxygen combines with all the commoner elements ex- 
cept fluorine there are a very large number of oxides: 
they may be divided into two classes according to the 
compound each forms when it reacts with water. When 
Lavoisier suggested the name "oxygen" he believed 
that the product formed by oxygen with any element 
was an acid and for many years a large number of 
oxides were accordingly called acids. 

2. Classes of Oxides. — When electropositive elements 
like sodium, potassium, calcium and the like unite with 
oxygen one class of oxides is produced and when the 
electronegative, like sulphur, phosphorus, etc., another 
class is obtained. The first are known as basic oxides 
and the second as acidic. The reasons for this will be 
seen later. 

3. Reaction of Water upon Basic Oxides. — If such ox- 
ides as sodium oxide and others named above as basic 
are put with water a reaction takes place as shown by 
the following equations: 

Na 2 + H 2 -> Na 2 H 2 2 =2NaHO 
K 2 + H 2 -> K 2 H 2 2 =2KHO 
CaO + H 2 -» CaH 2 2 =Ca(HO) 2 

The product formed in each case is a hydroxide, the 
positive part of which is the metal, while the negative 
part is common to all, the hydroxyl radical. These 
and many other similar compounds are called bases, 
hence the oxides from which they were derived were 
spoken of as basic oxides, or base-forming oxides. Not 
many bases may be formed directly from the action of 
water upon the corresponding oxides because not many 
oxides are soluble in water, hence no reaction is possible. 



OXIDES. ACIDS. BASES. AND SALTS 117 

4. What Is a Base? — All bases are hydroxides, as seen 
above. A base may be defined as a compound contain- 
ing the negative radical hydroxyl, and if soluble in 
water, turns red litmus blue and has a soapy, some- 
what bitter taste. Only a few bases are soluble in wa- 
ter. In addition to those named already may be added 
barium hydroxide. Ba(H0) 2 ; strontium hydroxide, 
Sr(HO) 2 ; and ammonium hydroxide. XH 4 H0. All such 
soluble hydroxides are called alkalies and they all attach 
the skin to a greater or less extent, hence some of them 
are spoken of as caustic ; thus, sodium hydroxide is 
often called caustic soda. 

5. Reaction of Water with Acidic Oxides. — "When 
such oxides as those of phosphorus, sulphur and the 
like are passed into water the reaction is shown by the 
following equations: 

S0 2 -H 2 0->H 2 S0 3 
SO -H 2 0-^H 2 SO, 



C0 2 - H 2 -> H 2 CO 
P 6-, - 3H o -> 2H.P0 4 



3 



The product in each case is an acid instead of a hydrox- 
ide. All the main chemical properties are essentially 
different from the compounds obtained above in Sec- 
tion 3. The positive part of these compounds is hydro- 
gen as will be found by putting a metal with them, in 
that the more positive metal will expel the hydrogen. 
These compounds are called acids and the oxides which 
produced them, acidic oxides as already mentioned. A 
very considerable number of acids may be produced 
directly by adding the oxide to water but not nearly 
all. Such oxides as these are commonly called anhy- 
drides. Defining. Ave would say that an anhydride, or as 



118 CHEMISTRY FOR NURSES 

some call them, an acidic anhydride, is an oxide which 
will form an acid on the addition of water, or more 
briefly, an anhydride is an acidic oxide. 

6. Definition of an Acid. — It is not an easy matter 
to define an acid. It is a compound whose positive part 
is hydrogen and if soluble in water will turn blue lit- 
mus red and has a sour taste. As most acids are derived 
from oxides either practically or theoretically they usu- 
ally contain oxygen as a part of the negative radical; 
but hydrochloric and several others we may meet with, 
not being derived from oxides, contain no oxygen. 

7. How Bases Are Named. — It was stated early in the 
study of compounds that in naming them we always 
give the electropositive part first. Hence as the pos- 
itive part of such compounds, generally speaking, is 
a metal, we give the name of this and then as the nega- 
tive part is hydroxl, w r e add that. Thus, 



+ 


- 


+ 


- 


Sodium 


hydroxide 


Na 


HO 


Calcium 


hydroxide 


Ca 


(HO) 2 


Copper 


hydroxide 


Cu 


(HO) 2 


Ammonium 


hydroxide 


NH 4 


HO 



It will be noticed that the last named base does not 
contain a metal: it is the only exception we shall meet 
with; but the group, NH 4 , has many of the properties 
of a metal, one of w r hich is its power of forming a 
hydroxide. 

8. How Acids Are Named. — As the positive part of 
acids is hydrogen, we should expect them to be called 
hydrogen something, as we have called the gas hydro- 
gen chloride before we made a solution of it by pass- 
ing it into water. From the fact that several of the 



OXIDES, ACIDS. BASES, AND SALTS 119 

commoner acids were discovered and in daily use be- 
fore any system of nomenclature was adopted, the ef- 
fort, made later, to apply the system did not meet with 
favor; hence, Ave still say 

Sulphuric Acid and not Hydrogen Sulphate for ELSC^ 
Carbonic Acid and not Hydrogen Carbonate for H 2 C0 3 
It is not wrong, however, to use the latter plan, but 
the common method is to use the name of the nonmetal 
in the oxide forming the acid and then add the word 
acid. Thus, 

C0 2 is Carbonic Anhydride ; with water it forms Car- 
bonic Acid, H 2 C0 3 

S0 3 is Sulphuric Anhydride ; with water it forms Sul- 
phuric Acid, H 2 S0 4 

P 2 5 is Phosphoric Anhydride ; with water it forms 
Phosphoric Acid H 3 P0 4 

As seen, however, some acids contain no oxygen. To 
emphasize this fact, they all prefix the term hydro, thus: 

HC1 is ZTycZrochloric Acid, while HC10 3 is Chloric Acid 
HBr is H ydrohromie Acid ; HBr0 3 is Bromic Acid 
HI is Hydriodic Acid ; HI0 3 is Iodic Acid 

Sometimes the electronegative element like sulphur 
forms more than one oxygen acid, thus: 

H 2 S0 4 Sulphuric Acid 
H 2 S0 3 Sulphurous Acid 
HN0 3 Nitric Acid 
HX0 2 Nitrous Acid 
H 3 P0 4 Phosphoric Acid 
H 3 P0 3 Phosphorous Acid 

In all these cases, which are typical, it will be noticed 
that the acid with the smaller amount of oxygen has 
the ending ous. 



120 CHEMISTRY FOR NURSES 

9. Familiar Acids. — Students commonly have the idea 
that acids are liquids and that most or all liquids found 
on a laboratory shelf are acids. This is far from the 
truth. In fact most acids are solids and the greater 
portion are white crystalline substances. There are a 
few gases, as hydrogen chloride, fluoride, cyanide 
(prussic acid) : some few are liquids, like sulphuric and 
nitric; but most are solids. Such are tartaric, citric, 
lactic, picric and many others. 

10. Salts. — There is one other class of compounds, 
very abundant, known as salts, because so many of them 
resemble common salt. To the chemist a salt is a com- 
pound formed by the union of a base and an acid. The 
process is called neutralization, because when complete 
both the base and the acid have lost their characteristic 
properties; that is, they have had their basic or acidic 
properties destroyed or rendered neutral. The follow- 
ing equations illustrate the process: 

NaHO + HC1 -* NaCl + H 2 
KHO + HC1 -> KC1 + H 2 
Ca(HO) 2 + H 2 S0 4 -> CaS0 4 + 2H 2 
Mg(HO) 2 + H 2 S0 4 -> MgS0 4 + 2H 2 

It will be noticed that in every case water is formed 
besides the salt. Similar results are obtained if the 
corresponding basic oxide is used instead of the base, 
except the amount of water is less: 

CaO + H 2 S0 4 -» CaS0 4 + H 2 
MgO + H 2 S0 4 -> MgS0 4 + H 2 

11. Three Kinds of Salts. — If the neutralization is 
complete, which is the case when there is one positive 



OXIDES, ACIDS, BASES, AND SALTS 121 

hydrogen in the acid for each negative hyclroxyl in the 
base, the salt formed is a neutral or normal salt. All 
of those shown above are of this class. Sometimes there 
is an excess of hydrogen in the acid over the hydroxy] 
in the base: in such cases the excess of acid hydrogen 
remains in the salt formed and gives it some of the prop- 
erties which the hydrogen had in the acid or of the acid 
itself and all such are called acid salts. Defined, an 
acid salt is one which contains some of the positive 
hydrogen from the acid used in making the salt. Thus: 

2NaHO + H 2 S0 4 -> Na 2 S0 4 + 2H 2 
NaHO - H 2 S0 4 -» NaHS0 4 - H 2 

The second is an acid salt and will turn litmus red in 
color just as the original sulphuric acid will and the salt 
also has a sour taste, which is characteristic of acids. 
It must be observed, however, that not every salt con- 
taining hydrogen is an acid salt. The hydrogen must 
have come from the positive part of the acid to make 
the salt an acid salt. Thus: 

NH.HO + HX0 3 -> NH 4 N0 3 + H 2 
NaHO + HC 2 H 3 2 -* NaC 2 H 3 2 + H 2 

Neither of these salts is an acid salt, although both con- 
tain hydrogen, for the acid hydrogen in both cases ex- 
actly neutralized the basic hydroxyl and left none in 
the salt. 

If the hydroxyl is in excess instead of the hydrogen, 
then we have what is known as a basic salt. Thus, 
C11CO3 is normal copper carbonate while Cu(HO) 2 CuC0 3 
is a basic carbonate. We shall not meet often with 
basic salts in our work, hence little need be said here 
regarding them. 



122 CHEMISTRY FOR NURSES 

12. How Salts are Named. — Normal salts are named 
as already explained in the study of compounds, that is 
by reading the name of the positive part of the com- 
pound and following this with the name of the electro- 
negative element or group. If the compound is a bi- 
nary, that is, if it contains only two elements, then the 
ending is ide. Thus: 

KC1 Potassium Chloride 
MgO Magnesium Oxide 
CuS Copper Sulphide 

If the negative part of the compound is a radical group 
of an acid whose name ends in ic the salt name ends 
in ate. Thus: 

KCIO3 Potassium Chlorate, from HC10 3 , Chloric Acid 
Mg(N0 3 ) 2 Magnesium Nitrate, from HN0 3 , Nitric Acid 
CuS0 4 Copper Sulphate, from H 2 S0 4 , Sulphuric Acid 

We have seen, however, that there are sometimes two 
anhydrides of the same electronegative element, as for 
example, sulphur forms both S0 3 and S0 2 each of which 
forms an acid with water; and each of these acids forms 
salts with bases. Thus: 

Sodium Sulphate 
Sodium Sulphite 

So 

Potassium Nitrate 
Potassium Nitrite 

It will be seen, therefore, that salts formed from an 
acid whose name ends in ous, have names ending in ite. 

13. Acid Salts Named, How. — Acids which contain 



S(V 


-> H 2 S0 4 


-h> Na 2 S0 4 


so 2 - 


— > H 2 S0 3 


-* Na 2 S0 3 


;o, 

N 2 5 


-*HN0 3 


-»KN0 3 


N 2 3 


-* HN0 2 


^KN0 2 



OXIDES. ACIDS. BASES, AND SALTS 123 

two positive hydrogens can not form more than one 
acid salt with any base, hence in reading them we sim- 
ply prefix the term acid, thus: 

NaHS0 4 is Acid Sodium Sulphate or Sodium Hydrogen 
Sulphate 

KHCO, is Acid Potassium Carbonate, or Potassium Hy- 
drogen Carbonate 

Acids which contain three positive hydrogens may form 
two acid salts with a given base, in which case it is 
not sufficient to prefix the term acid, as there are two 
acid salts. Thus, 

H 3 P0 4 may form KH 2 P0 4 and K 2 HP0 4 ; to distinguish 
between these we use a prefix designating the number 
of metallic atoms or groups introduced. Thus, the first 
of the salts named just above has one potassium atom 
and this is called ^^^opotassium phosphate, while the 
other is called d /potassium phosphate. 

14. Binary Salts. — Binary salts are formed from the 
acids which contain no oxygen, and all have names end- 
ing in ide as already stated. However, there may be 
two of these for any given base: thus, there is Hg 2 Cl 2 
and HgCl 2 . In such cases the compound having the 
greater relative amount of the positive element is called 
by a name ending in ons, in the sense of full of, while 
the other receives the ending ic. Thus: 

Hg 2 Cl 2 is Mercurous Chloride 
HgCL is Mercuric Chloride 
CuS is Cupric Sulphide 
Cu 2 S is Cuprous Sulphide 
FeS is Ferrous Sulphide 
Fe 2 S 3 is Ferric Sulphide 



124 CHEMISTRY FOR NURSES 

Exercises for Review 

1. "What is an oxide? Name five. What was the old idea of 
oxides? 

2. What two classes of oxides are there? Give three examples 
of each. 

3. What is a basic oxide? Why so called? 

4. What is a base? Name four with formulas. 

5. What is an alkali? Name five with formulas. 

6. What is an acidic oxide? Name three. Define anhydride 
and illustrate. 

7. Define an acid. Name two classes and state how different 
in composition. 

8. How are bases named? Give three illustrations. 

9. How are acids named? Give three illustrations. 

10. How are acids with no oxygen named? Illustrate. 

11. Give the names of H SO , H SO , HNO , HNO , H PO , 

2 3> 2 4' 3' 2> 3 4' 

H 3 P0 3 . 

12. Give the names of HC1, HC10 3 , HBr, HBrO , HF, HI, 
HI0 3 . 

13. Name two gaseous acids; two liquid; two solid. 

14. What is a salt? What is neutralization? Illustrate. 

15. What two products always form in neutralization? 

16. Name and give illustration of three kinds of salts. 

17. Classify each of the following salts: KC10 o , KHSO^, 
K CO , NaHCO , K HPO , KH PO , KNO . 

2 3* 3' 2 4' 2 4' 3 

18. How are binary salts named? Illustrate. 

19. How are ternary salts named? Illustrate. 

20. How are two acid salts from the same acid distinguished 
from each other? 

21. Give names of KHP0 4 , KH 9 P0 4 , N-a,HB0 3 , NaH 2 B0 3 . 

22. Give names of Cu*S, CuS, HgO, Hg 2 0, 2 SnCl * SnCl 4 , 2 As^0 3 , 

AS 2 5- 

23.° Classify and give names: KHO, H 3 P0 4 , H 3 P0 3 , Ca(HO)„, 
CaSO , K PO , KH PO , Na HPO , HBrO , HBr, KCIO . 

4' 3 3 ? 2 3 ? 2 4' 3> ' 3 



CHAPTER XII 

AMMONIA AND NITRIC ACID 

Outline — 

1. Ammonia, Historical. 

2. How Obtained — Commercial Supply. Quantities Wasted. 

3. Characteristics of Ammonia. 

4. Uses of Ammonia. 

(a) Ammonium Hydroxide in Household. 

(b) Ammonia Gas in Manufacture of Sodium Car- 

bonate. 

(c) Ammonia Liquefied for Kefrigeration. 

5. Nitric Acid. 

(a) In the Air. 

(b) Usual Way of Manufacturing. 

(c) Synthetic Process. 

6. Preparation of Nitric Acid. 

7. The Oxides of Nitrogen. 

(a) Names and Formulas. 

(b) Eelation to Nitric Acid. 

8. Nitrous Oxide. 

9. Characteristics of Nitric Acid. 

(a) Pure. 

(b) Commercial Variety. 

(c) Compared with Other Acids. 

10. Uses of Nitric Acid. 

(a) Making Coal Tar Dyes. 

(b) Making Explosives. 

Nitroglycerine. 
Dynamite. 
Guncotton, etc. 

(c) Eelated Products. 

Collodion. 
Celluloid. 
Fiber Silk. 
Exercises for Eeview. 

125 



126 CHEMISTRY FOR NURSES 

1. Ammonia, NH 3 . — Under the name " spirits of harts* 
horn" ammonia has been known for many years. Even 
as long ago as the time of Pliny it was known and he 
speaks of it as the vehement odor. It exists in the air 
in minute quantities, due to the decomposition of cer- 
tain animal products and other nitrogenous bodies. 

2. Source of Supply. — Since coal is the result of a 
metamorphosed vegetation, it contains much nitrogen; 
hence when soft coal is heated, ammonia is one of the 
products formed, just as has already been mentioned 
in cases of slower decomposition. Most of the am- 
monia of commerce has, therefore, for a good many 
years been obtained as a by-product in the manufacture 
of coal gas. The various products from the coal are 
passed through washers filled with lumps of coke or 
some similar material or lattice work, kept damp by 
water dripping over it, whereby the ammonia is ab- 
sorbed. This is neutralized by dilute hydrochloric or 
sulphuric acid and ammonia distilled from it by treat- 
ment with lime. The following equations show the 
steps: 

Coal, heated —> Impure ammonia + other products 

NH 3 + H 2 -> NH 4 HO (impure) 
H 2 S0 4 + 2NH 4 HO (impure) -*(NH 4 ) 2 S0 4 (impure) 

(NHJ 2 S0 4 + CaO -> 2NH 3 + CaS0 4 + H 2 

A vast amount of soft coal is made into coke for the 
smelting of metallic ores ; ammonia and other valuable 
gases are produced here as in the manufacture of il- 
luminating gas, yet with characteristic American waste- 
fulness only about 20 per cent of this is saved, while 
the remainder has been allowed to escape into the air. 
At the same time the United States has been importing 
fertilizer to the value of millions of dollars when it 



AMMONIA AND NITRIC ACID l27 

could all have been supplied from these coke ovens by 
converting the wasted ammonia into ammonium sul- 
phate as shown by the equations above. 

3. Characteristics of Ammonia. — Ammonia is a col- 
orless gas with a strong, penetrating odor, producing 
strangulation and bringing tears to the eyes. In solu- 
tion it has a bitter, soapy taste and is strongly caustic. 
It is the most soluble of gases, one volume of ice water 
being able to dissolve twelve or thirteen hundred vol- 
umes of the gas. At ordinary temperatures one liter 
of water will dissolve about 800 liters, giving a solu- 
tion containing about 28 per cent ammonia. The gas 
will not burn in the air nor support the combustion of 
other substances ; it is a little more than half as heavy 
as air, haA^ing a specific gravity of about 0.6. It may 
be readily liquefied by cold and pressure and in the 
liquid form boils at -38.5° C. When passed into water 
the solution which takes place is a chemical one rather 
than physical, as the equation shows a new product 
formed, 

NH 3 + H 2 ±=> NH 4 H0. 

This new compound, however, is very unstable and the 
reaction is constantly reversing as shown by the double 
sign in the equation. 

4. Uses of Ammonia. — In the form of dilute ammo- 
nium hydroxide it is used in the household frequently 
for cleansing purposes, softening water and other sim- 
ilar ways. In commerce it is extensively used in the 
manufacture of sodium carbonate by the Solvay proc- 
ess which will be described at another time. It is also 
used in refrigeration very extensively. For this the 



128 



CHEMISTRY FOR NURSES 



liquefied form is employed as shown in Fig. 24. It is 
allowed to flow from the containing cylinder into pipes 
surrounded by brine whose freezing point is not less 
than -12° C. Surrounded by these pipes are galva- 
nized iron boxes containing the water to be frozen. A 
pump attached to the ammonia pipes is constantly ex- 
hausting the pipes and thereby maintaining a rapid 
evaporation ; it is this evaporation which produces the 



| WATER TANK 

72 



MMMi 



mmm 






CONDENSER 
PIPES 




BRINE TANK 



NEEDLE VALVE 






i tewd g m ) 








\ \\\\\\\K\\\\\\\\\\\\\\\^\\\y ^^c 



Fig. 24. — Manufacture of ice. 



cold sufficient to lower the brine below the freezing 
point of pure water. Another pump receives the am- 
monia drawn from the pipes and compresses it to such 
an extent that when cooled by water flowing over the 
condenser pipes it again liquefies and is then ready for 
use again. It requires about one pound of ammonia to 
make three pounds of ice, but as the liquid can be used 
over and over the process of making artificial ice is 
not an expensive one. Sometimes the brine is pumped 



AMMONIA AND NITRIC ACID 129 

into a second chamber where the water is to be frozen. 
For cold storage purposes the brine is pumped through 
pipes into rooms wherever needed so that in markets, 
floral shops, and various other places pipes, heavily 
covered with frost, are often seen. 

5. Nitric Acid, HN0 3 . — As nitric acid is an oxyacid, 
theoretically it would be made from an oxide, its an- 
hydride. In every electrical storm some nitrogen oxides 
are formed by the union of atmospheric oxygen and 
nitrogen, and a little nitric acid is produced, therefore, 
from their solution in the rain. Two or three instances 
are on record, when the lightning was excessive and 
the rainfall slight, where the acid ivas sufficient to give 
a test. Generally speaking, however, it does not occur 
free. In the form of compounds it has been very 
abundant especially in Chile as saltpeter, or sodium 
nitrate. 

6. Preparation of Nitric Acid. — In the laboratory ni- 
tric acid may be made by distilling a mixture of sodium 
nitrate and strong sulphuric acid as shown in Fig. 25. 
If the process is continued long the condenser should 
be cooled by water. On a commercial scale the same 
process is employed. The reaction taking place is 
shown by the equation, 

NaN0 3 + H 2 S0 4 -> HNO s + NaHS0 4 . 

Owing to the limited supply of Chile saltpeter and the 
difficulty of obtaining it especially in times of war when 
it is most needed, another process is being rapidly de- 
veloped now wherever water power may be had. The 
fact that an electric discharge in the air will produce 
the anhydride of nitric acid has already been mentioned. 
This is the principle involved. Where electricity may 



130 CHEMISTRY FOR NURSES 

be had cheaply through water power, the air is forced 
through chambers where an electric discharge is con- 
stantly taking place with the result that one or more 
of the nitrogen oxides mentioned elsewhere are pro- 
duced. When these are treated with water, nitric acid 
is the result. 




Fig. 25. — Preparation of nitric acid. 

7. Nitrogen Oxides. — There are five of these oxides, 
most of them of little interest to the student except for 
the one fact just mentioned. They are 
Nitrogen Monoxide, Nitrous Oxide, N 2 
Nitrogen Dioxide, Nitric Oxide, N 2 2 , usually written 

NO 
Nitrogen Trioxide, Nitrous Anhydride, N 2 3 
Nitrogen Tetroxide, Nitrogen Peroxide, N 2 4 , usually 

written N0 2 
Nitrogen Pentoxide, Nitric Anhydride, N 2 5 

The last three of these may directly or indirectly pro- 
duce nitric acid on the addition of water, thus: 



N 2 3 + H 2 0-^2HN0 2 
N 2 4 + H 2 0->HN0 2 + 
N 2 5 + H 2 0->2HN0 3 



AMMONIA AND NITRIC ACID 131 

It is thus seen that the first produces nitrous acid alone 
while the second nitrous and nitric mixed. But nitrous 
acid is easily changed to nitric by the addition of oxy- 
gen so that any one of these three oxides will produce 
ultimately the nitric acid desired. 

8. Nitrous Oxide, Laughing Gas, N 2 0. — Nitrous ox- 
ide is obtained by gently heating ammonium nitrate as 
shown by the equation, 

NH 4 N0 3 (heated) ->N 2 + 2H 2 

The chief interest attached to this gas is its use as an 
anesthetic. Mixed with oxygen, it is used in minor 
operations such as tooth extractions or where but lit- 
tle time is needed. It is an intoxicant and has a vari- 
ety of effects upon different individuals. Ultimately 
if continued it produces insensibility and death. 

9. Characteristics of Nitric Acid. — Nitric acid if pure 
is a perfectly colorless liquid; but in its manufacture 
some of the oxides of nitrogen especially the peroxide 
are apt to be present, giving it a brown color. If pure, 
its boiling point is 86° C. and density 1.56. It is unsta- 
ble in this form and is put upon the market with a 
strength of about 68 per cent and a specific gravity of 
1.42. Even at this strength heat and bright sunlight 
decompose it somewhat so that the brown fumes of 
nitrogen peroxide appear and discolor the liquid. A 
small addition of water will remove this. It discolors 
the skin and clothing, staining them yellow; this can 
not be removed by any treatment, though the garment 
may be dyed and the spot removed in that manner. 
Nitric acid is a strong oxidizing agent as it readily 
gives up its oxygen, thus: 



132 CHEMISTRY FOR NURSES 



2HN0 3 -> H 2 + 2N0 2 + 



On this account a piece of charcoal heated to redness 
and thrust into strong nitric acid will burn vigorously. 
For this reason, also, nitric acid behaves differently 
from most other acids toward metals. Instead of the 
hydrogen being liberated, the oxygen attacks the metal 
making an oxide of it, and then sometimes, the oxide is 
dissolved with the formation of a nitrate. 

10. Uses of Nitric Acid. — One important use is as an 
oxidizing agent in the manufacture from aniline of 
the various coal tar dyes, an industry whose output has 
a value of millions annually. Another is in the manu- 
facture of the various explosives used in numerous 
ways. Nitroglycerine is one of the more common. It 
is made by treating glycerine with fuming (brown) 
nitric acid, shown thus: 

C 3 H 5 (HO) 3 + 3HN0 3 -> C 3 H 5 (N0 3 ) 3 + 3H 2 

The C 3 H 5 (N0 3 ) 3 is the nitroglycerine, more properly 
called glyceryl nitrate. It will be observed for every 
molecule of it obtained in the reaction there are three 
molecules of water produced at the same time. It be- 
comes necessary to remove this water, otherwise the 
acid soon is so dilute that the reaction ceases. For 
this purpose fuming sulphuric acid is used which is a 
powerful dehydrating agent. The nitroglycerine then 
may be separated as a heavy oily liquid which does 
not mix with the diluted sulphuric acid. For the sake 
of convenience much of the nitroglycerine is made into 
dynamite ; this is done by adding sawdust in varying 
amounts giving different grades of giant powder as it 
is called. Sometimes a siliceous earth, capable of ab- 



AMMONIA AND NITRIC ACID 133 

sorbing large amounts of the oily nitrate, is used in- 
stead of sawdust. These explosives, as many others, 
are started by a detonator, like mercury fulminate, 
Hg(CNO) 2 . A sharp blow will ignite this and the shock 
will start the nitroglycerine. The explosive property 
depends, as it does in nearly all cases, upon the fact 
that nitrates are as a rule exceedingly unstable bodies. 
There is enough or nearly enough oxygen contained in 
the nitroglycerine molecule itself for the combustion 
of the other elements present. The hydrogen is burned 
to water, the nitrogen goes off free and the carbon 
becomes carbon monoxide and dioxide. The quantity 
of gas produced is, therefore, enormous in proportion 
to the original volume, and the violence correspond- 
ingly great. Moreover, the heat of combustion greatly 
expands these gases and thus even greater effects follow. 
Guncotton-Nitrocellulose. — As nitroglycerine is made 
by treating glycerine with fuming nitric acid and sul- 
phuric so is this explosive, except cotton takes the place 
of the glycerine. The sulphuric acid serves the pur- 
pose of a dehydrating agent as before. Cellulose has 
the formula, (C G H 10 O 5 ) n and when treated with nitric 
acid we may introduce from three to six nitrate groups, 
the higher forms of the explosive having six groups. 
Its formula is C 12 H 14 4 (N0 3 ) 6 . It is- produced from 
two groups of the cellulose formula thus : 

2C 6 H 10 O 5 + 6HNO3 -> C 12 H 14 4 (N0 3 ) 6 + 6H 2 

Lighted in the open air it burns quietly, but detonated 
the combustion is almost instantaneous and the results 
terrific. In the lower form, the cellulose ternitrate, 
the explosive power is much less; it is frequently dis- 
solved in ether and alcohol mixed and forms what is 



134 



CHEMISTRY FOR NURSES 



known as collodion, used in photography and as new 
skin in surgery. When dissolved in camphor it pro- 
duces celluloid, while fiber silk is cotton nitrated as 
above, dissolved as for collodion, then in pasty form is 
forced through tiny openings like the spinneret of the 
silk worm. The explosive nitrate groups are then re- 
moved by further chemical treatment with calcium 
sulphide or some alkaline reagent. The appearance is 
not greatly different from real silk but the wearing 
qualities are considerably less, as the fiber is more 
brittle. 




Fig. 26. — Some forms of smokeless powder. 

Smokeless Powders and T. N. T. — When the hex- 
anitrate of cellulose is treated with ether it forms a 
gelatinous mass which is pressed into molds of various 
shapes some of which are shown in Fig. 26 adjoined and 
sold under the name of smokeless powders. The 
products of combustion are the same as those men- 
tioned in the case of nitroglycerine, all of which are 
colorless gases. Picric acid, otherwise known as trini- 
trophenol, with a formula of C 6 H 2 (N0 2 ) 3 OH, is not 
only very explosive itself, but serves as the starting 
point for other high explosives. At the present time, 
October, 1918, we hear a great deal about T. N. T. a 
commercial term for trinitrotoluol. Its formula is 



AMMONIA AND NITRIC ACID • 135 

C 6 H 2 (N0 2 ) 3 CH 3 , and it is being used extensively in the 
high explosives in warfare. Toluol is a compound ob- 
tained from coal tar just as phenol or as it is often 
called, carbolic acid, is, and its explosiveness lies in the 
nitro groups as in all other cases considered. 

Exercises for Review 

1. Give two old names for ammonia. Why was it called thus? 

2. What is the source of our commercial supply? How has it 
been allowed to go to waste? 

3. Give the characteristics of ammonia? What other gas 
studied is also very soluble in water? How many barrels of am- 
monia gas will a quart of ice water dissolve? 

4. What is produced when ammonia dissolves in water? 

5. Name three uses of ammonia. Describe a refrigeration 
plant. 

6. How may nitric acid occur in the air? 

7. Give the usual way of manufacturing nitric acid. What 
newer process is being developed? 

8. Name the oxides of nitrogen and give formulas. 

9. Which of these is used medicinally? Why can it not take 
the place of ether or chloroform? 

10. Why are the last three in the series of any interest to us? 

11. Give the characteristics of nitric acid. 

12. How does nitric acid behave differently toward metals 
from most other acids? 

13. Name two industries with which nitric acid is closely as- 
sociated. 

14. What is the purpose of the two acids used in the manufac- 
ture of nitroglycerine? 

15. What is dynamite? Giant powder? What advantage 
over nitroglycerine ? 

16. What is a detonator? Name the usual one. 

17. How is guncotton made? What different varieties? 

18. What is collodion? New skin? Celluloid? Fiber silk? 

19. How are smokeless powders made? What advantage have 
they? 

20. What is T. N. T.? Its use? 

21. Wherein lies the explosive character of the various sub- 
stances named? 



CHAPTER XIII 
VALENCE 

Outline — 

1. Meaning of Valence. 

Univalent Atoms and Groups. 

2. Bivalent Atoms and Groups. 

3. Trivalent and Quadriva^nt Atoms and Groups. 

4. Variation in Valence. 

(a) Apparent, Not Keal. 

(b) Unsaturated Compounds. 

(c) Experimental Evidence. 

5. Valence of Elements in Ternary Compounds, 
u. Terms Used in Valence. 

Exercises for Eeview. 

1. What Is Valence? — The term, valence, is derived 
from a Latin word which means power: so in chemistry 
valence simply means power, the power which an atom 
or group of atoms acting together in a radical, has of 
combining with something taken as a standard. This 
standard of measurement is the hydrogen atom. So 
when an atom like chlorine has. the power of combin- 
ing with one atom of hydrogen and no more it is said 
to have a valence of one. This is shown in the com- 
pound, hydrogen chloride. Likewise, iodine has a 
valence of one, also bromine and fluorine, as each of 
them combines with one atom of hydrogen. This is 
seen in the compounds, HI, HBr, and HF. Positive ele- 
ments, not being able to combine with hydrogen, must 
be measured by some electronegative, whose valence 
we have already measured by hydrogen. Such an ele- 

136 



VALENCE 137 

ment is chlorine as it combines with practically all 
the positive elements. Thus, sodium has a valence of 
one, seen in the compound, NaCl: the same is true of 
potassium, seen in KC1. There is one positive radical with 
a valence of one, ammonium, seen in NH 4 C1; also sev- 
eral negative radicals. For example, HO, seen in 
NaHO; C10 3 , seen in KC10 3 , N0 3 , seen in KN0 3 , etc. 

2. Elements with a Valence of Two. — The most com- 
mon element with a valence of two is oxygen and as it 
combines with nearly all other elements it often servers 
as a means of measuring the combining power of the 
others. Water, H 2 0, shows that oxygen has a valence 
of two. Sulphur forms the compound, hydrogen sul- 
phide, H 2 S, which indicates a valence of two for sul- 
phur. Several of the common metals have a valence 
of two as shown by their oxides: thus, magnesium, MgO, 
copper, CuO, zinc, ZnO, etc. Two common radicals, 
S0 4 , seen in sulphuric acid, H 2 S0 4 , and C0 3 , seen in all 
carbonates, as carbonic acid, H 2 C0 3 , have a valence of 
two. 

3. Valence of Three and Four. — Nitrogen and phos- 
phorus both form hydrogen compounds, as NH 3 , am- 
monia, and phosphine, PH 3 . The radicals, P0 4 and 
B0 3 , seen in phosphoric and boric acids respectively 
each has a valence of three, shown by their formulas, 
H 3 P0 4 , and H 3 B0 3 . For a valence of four carbon and 
silicon are the best examples, seen in the compounds 
carbon dioxide, C0 2 , and silicon dioxide, Si0 2 . We 
have met with no radical up to this time having a va- 
lence of four, but orthosilicic acid has the formula, 
H 4 Si0 4 , showing for Si0 4 a valence of four. 

4. Variation in Valence.— In studying the binary 
compounds we noticed such as mercuric and mercurous 



138 CHEMISTRY FOR NURSES 

chloride and many others. Thus, HgCl 2 and Hg 2 Cl 2 , in 
the first of which mercury combines with two atoms of 
chlorine and in the second, one atom mercury combines 
with one of chlorine. Probably this atom always has 
the valence of two and is not variable ; such compounds, 
then, as mercurous chloride, Hg 2 Cl 2 are unsaturated 
and may be represented by the structural formula 
thus: 

TX _._ and then if the molecule consists of the two 
— Hg — CI 

unsaturated groups, as most believe, it is possible that the 
two unused bonds of the two mercury atoms " swing 
around ' ' and hold loosely to each other. This is merely an 
assumption, however, as we know nothing about what 
this bond is. We do know, however, that the mercu- 
rous atom will readily take up another atom of chlorine 
and form the mercuric chloride. Again, iron forms 
two sets of compounds in the same way illustrated by 
the two chlorides, FeCl 2 and FeCl 3 , ferrous and ferric 
chloride. As in the case of the mercury the ferrous 
compound is an unsaturated one and the real valence 
of the iron atom is three and not two. As proof of this 
the ferrous compounds are all very unstable and 
readily take some other electronegative element or 
group to complete the saturation. Another good ex- 
ample is carbon: we shall see that it forms two oxides, 
CO, and C0 2 . We shall have good evidence also that 
carbon monoxide is an unsaturated compound in that 
it readily takes up more oxygen to form the dioxide. 
Many other cases of this kind are known in carbon 
compounds. Thus ethane, C 2 H 6 , is a saturated com- 
pound, each carbon atom having all four bonds in use, 
as shown by the following graphic formula: 



VALENCE 139 

H H 



C 2 H 6 H— C— C— H 



H H 



H H 

I I 
while ethylene, C 2 H 4 , with graphic formula, — C — C — 

I I 
H H 

has two bonds with nothing attached. As experi- 
mental proof of this, if the first of these two com- 
pounds is passed through a solution of bromine, noth- 
ing happens, no matter how long the trial is continued: 
if the second is passed in the same way it is not long 
before the red color of the bromine solution has dis- 
appeared and in its place we have a colorless, oily 
liquid, which on analysis is found to contain two parts 
of bromine with the formula of C 2 H 4 Br 2 or shown 

H H 

graphically, thus: Br — C — C — Br. This is only one 

I I 
H H 
case of a large number that may be given. It seems 
probable, therefore, in the light of such experiments 
that most of the so-called variation of valence is not 
variation at all, but a case of one of the compounds of 
the element in consideration not being saturated. 

5. Valence in Ternary Compounds. — Often we wish 
to know the valence of a certain atom in a ternary 
compound. This is not difficult if it is remembered 
that the oxygen in the compound is the equivalent of 
both the other elements. Suppose it is desired to know 
the valence of chromium in potassium chromate, 
K 2 Cr0 4 . The valence of oxygen is two; four atoms 



140 CHEMISTRY FOR NURSES 

would therefore have a valence of four times two, or 
eight. Two atoms of potassium would have a valence 
of two ; subtracting the two of the potassium from the 
eight of the oxygen leaves six which is the valence of 
the chromium atom in the compound. 

6. Degrees of Valence Named How. — Two sets of 
terms are used in designating the degree of valence of 
any element or group. Thus we may use the words 
monad, diad, triad, tetrad, pentad; or we may say uni- 
valent, bivalent, trivalent, quadrivalent, quinquivalent. 
Thus chlorine is a monad or a univalent element; car- 
bon is a tetrad or a quadrivalent element. 

Exercises for Review 

1. What is meant by valence? What is our unit of measure- 
ment? Illustrate. 

2. How can you determine the valence of an element if it 
will not combine with hydrogen? Illustrate. 

3. Name four elements and four radicals with a valence of 
one. 

4. Name four elements and two radicals with a valence of 
two. 

5. What is the most common element with valence of two? 

6. Name some elements with valence of three; some with four. 
Give proof. 

7. What evidence can you give that valence of mercury atom 
is two when sometimes it appears to be one? 

8. Give experimental evidence that ethane is a saturated com- 
pound; that ethylene is not saturated. 

9. What do you understand by a saturated compound? An 
unsaturated one? 

10. What is a graphic formula? Illustrate. 

11. What is the valence of sulphur in sulphuric acid? Of 
manganese in potassium permanganate, KMnO ? Of Cr in 
K Cr O ? 

2 2 7 






CHAPTER XIV 
CARBON AND A FEW COMPOUNDS 

Outline — 

1. Distribution of Carbon in Nature. 

2. Forms of Carbon. 

(a) Crystallized — 

Diamond. 
Graphite. 

(b) Amorphous. 

Natural. 

Coals. 
Artificial. 

Charcoal. 

Coke. 

Lampblack. 

Gas Carbon 

3. The Diamond. 

(a) Proof of Composition. 

(b) Comparison with Allotrope, Graphite. 

(c) Origin of Diamonds. 

(d) Artificial. 

(e) Uses. 

4. Graphite. 

(a) Characteristics. 

(b) Uses 

5. Charcoal. 

(a) Preparation. 
'(b) Uses. 

6. Coke. 

7. Coal Gas. 

(a) Preparation. 

(b) By-products. 

8. Gas Carbon. 

141 



142 CHEMISTRY FOR NURSES 

9. Natural Coals. 

(a) Formation. 

(b) Varieties. 

(c) Natural Gas. 

(d) Petroleum. 

10. Compounds of Carbon. 

(a) Carbon Monoxide. 

Various Sources of. 
Danger of. 

(b) Carbon Dioxide. 

Value of. 
Practical Uses. 

(c) Carbon Tetrachloride. 

Practical Uses. 

(d) Carbides. 

Calcium Carbide. 
Silicon Carbide. 
Iron Carbide. 
Exercises for Keview. 

1. Distribution in Nature. — Carbon is an interesting 
element because of the variety of forms in which it ap- 
pears. In marble, limestone, corals, and similar forms 
it exists as a carbonate, crystallized or not, and often 
beautifully colored. It is in the air in the form of car- 
bon dioxide and is also familiar in many ways in the 
free state more or less pure and very widely dis- 
tributed. 

2. Allotropic Forms. — The purest form of carbon is 
the diamond: allotropic of this is graphite, and the ar- 
tificial forms of charcoal, coke, gas carbon and lamp- 
black. The various coals known to all are not pure 
carbon, but contain in addition some hydrogen, nitro- 
gen, and smaller quantities of some other substances. 

3. The Diamond. — Looking at a diamond and a piece 
of graphite, one could hardly believe that they are the 
same substance. It is not difficult, however, to prove 



CARBON AND A FEW COMPOUNDS 143 

that they are both carbon, for each, burned in an at- 
mosphere of oxygen, produces only one substance, 
carbon dioxide. If a diamond is heated strongly in the 
absence of air it swells up and becomes dark, re- 
sembling graphite somewhat; but if heated to 700° C. 
in a tube filled with oxygen it disappears, and leaves 
little or no residue, while in place of the oxygen we now 
have carbon dioxide. See Fig. 27 to show method. The 
diamond is put into the bulb of the combustion tube, a 
current of oxygen is then passed through to remove the 
air, the ends are closed loosely and the heat applied with 
results as stated. 

Comparison of Diamond with an AUotropic Form. — 
The diamond is the hardest mineral known, but 
graphite is one of the very softest; the diamond is 




"- - diamond 

Fig. 27. — Burning of a diamond. 

colorless, graphite is black; diamond is a poor con- 
ductor of electricity, graphite a good conductor; dia- 
mond has a density 3.5 times as heavy as water, 
graphite 2.3 times, and charcoal, another allotrope, 
has a density less than 2 ; diamond crystallizes in 
octahedrons and graphite in hexagonal plates. So 
it seems, if they were entirely different substances, they 
could hardly be more different than they are. 

Origin of Diamonds. — Nothing positive can be as- 
serted regarding the origin of diamonds, but they are 
believed to have been produced under great pressure, 
and sufficient heat to render the carbon more or less 
nearly molten. AYe have some evidences of this in the 
artificial diamonds made by the French chemist Mois- 



144 



CHEMISTRY FOR NURSES 



san some few years ago. The carbon he used was ob- 
tained by charring loaf sugar; this was mixed with 
iron turnings and placed in an electric furnace. 
Molten iron has the power of dissolving carbon, hence 
portions of the carbon thus entered into solution. Mois- 
san then plunged the whole mass into ice water, where- 
upon the outer portions of the molten iron solidified 
and thus put great pressure upon the interior portions 
of the mass. In this way the dissolved carbon crystal- 
lized. When the mass was cool it was broken up, and 
the iron dissolved away by nitric acid. This left the 




Fig. 28. — Moissan's electric furnace. 



diamonds in his beaker. Unfortunately they were all 
very small and more or less dark colored, but in other 
respects they had the properties of natural diamonds. 
See Fig. 28 which shows the form of electric furnace 
used by Moissan. 

Uses of Diamonds. — In ancient times diamonds A\ r ere 
prized for their beauty but as no way was known of 
cutting them they did not come into general use as or- 
naments until it was discovered they might be ground 
in their own dust. The largest diamond ever found 
weighed 3032 carats before cut; this was known as the 
Cullinan. Diamonds of such size are of little use, how- 



CARBOX AND A FEW COMPOUNDS 145 

ever, unless cut into smaller ones. Such as are imper- 
fect and unsuited as ornaments, are made into bear- 
ings for delicate instruments such as fine watches, 
assay balances, and the like. They are also mounted 
for cutting glass, for drilling through difficult rock 
formations, sawing stones, and as dust for cutting and 
polishing other precious stones. 

4. Graphite. — Nearest related of the allotropic forms 
of the diamond is probably graphite. It is not abun- 
dantly found in nature and to meet the present demand 
considerable is manufactured in electric furnaces. It 
has a soft, greasy feel, is very friable, not affected by 
the air or high temperatures, a good conductor of elec- 
tricity. On account of these properties it has many 
uses. The most familiar to the general public is in the 
form of the so-called lead pencils, named thus when 
the character of graphite was misunderstood. The 
various grades of pencils, ranging from soft to very 
hard are obtained by thoroughly mixing varying 
amounts of fine clay with the powdered graphite, mak- 
ing it into a thick paste and forcing it through tiny 
apertures in the shape of the familiar "leads." As 
it is not affected by the air it is used to coat shot, the 
grains of black and giant powder and as a polish for 
stoves. Because of its resistance uo heat it is used in 
crucibles, and on account of conductivity, in various 
ways in electrical applications. For example, in mak- 
ing electrotypes for printing books and magazines, the 
wax impression is coated with powdered graphite be- 
fore it is possible to obtain a deposition of the copper as 
the basis of the plate. 

5. Charcoal. — Charcoal is an artificial allotrope of 
the diamond. Formerly it was made by covering wood 
with earth and sod and by burning some considerable 



146 CHEMISTRY FOR NURSES 

portions of it the remainder was left as charcoal. It 
was an exceedingly wasteful method and is no longer 
followed. Now, the wood is placed in iron retorts and 
heated from beneath by coal which is a much cheaper 
fuel. Besides saving the wood formerly consumed for 
heat, such by-products as acetic acid, wood alcohol and 
acetone as well as several others which are now saved, 
more than pay the cost of manufacture. Besides wood, 
vast quantities of bone are made into charcoal; and 
just at the present time, considerable amounts of cocoa- 
nut shells and those of other nuts as well as the pits 
of the peach and other fruits. 

Uses of Charcoal. — The uses of wood charcoal are 
familiar to most. Besides as a fuel in braziers and 
other small open fires, it is used in filters for cisterns in 
country homes. In such cases it should be removed at 
least once a year and heated red hot to destroy im- 
purities. Bone charcoal, or bone-black, as it is often 
called, is used mainly for clarifying sugar and other 
organic compounds. It is considerably more porous 
than wood charcoal hence has greater absorptive pow- 
ers. Ivory black, a well known black paint, is made 
from tusks and similar animal products, such as are 
not suited for manufacture into more valuable arti- 
cles. Charcoal made from nutshells has especially 
strong absorptive powers and has been used in re- 
search laboratories in isolating the rare gases of the at- 
mosphere for some years: but it remained for the 
World War to create a great demand for such char- 
coal. • During 1918 carloads of nut shells were made 
into charcoal for use in gas masks. 

6. Coke. — As charcoal is made from wood, so coke 
is made from certain varieties of coal. It is placed in 



CARBON AND A FEW COMPOUNDS 147 

retorts or often in "bee-hive" ovens and heated 
strongly until the volatile products have passed off. 
The residue is a dark, grayish product, used largely in 
foundries and smelters for fuel and reduction pur- 
poses. It gives a much more intense heat than the 
coal from which it is made would give and is desirable 
for this reason. 

7. Coal Gas. — "When soft coal is heated in retorts as 
indicated in the preceding section, several combustible 
gases are expelled: when these have been purified, they 
constitute the coal gas used as cooking fuel and for 
lighting in most cities. Besides the combustible gases 
driven off two other volatile products are obtained. 
The first of these is coal tar, and the second is am- 
monia. The second has already been mentioned in an- 
other chapter. Coal tar is a very complicated mixture 
of numerous compounds, black because of the presence 
of small amounts of free carbon particles. In some 
ways it is the most wonderful mixture known to the 
chemist, From it are obtained the compounds from 
which are prepared nearly all the beautiful dyes now 
used in commerce ; most photographic developers and 
many indicators, of inestimable value to the chemist, 
have their source here ; many headache and other med- 
icines are made from coal tar products; phenol, . car- 
bolic acid, and its derivative picric acid, together with 
explosives made from it; toluol and trinitrotoluol also 
originate here. And with this the story is probably 
not half told. 

8. Gas Carbon. — In the manufacture of coke in re- 
torts a hard, fine-grained deposit slowly forms upon 
the interior of the retorts. At intervals this is scraped 
off, ground up and molded into various shapes for use. 



148 CHEMISTRY FOR NURSES 

It is an excellent conductor of electricity and one 
familiar use of it is in the carbon sticks used in arc 
lights for street and other lighting. It is also used in\ 
dry cells as one of the electrodes. 

9. Natural Coals. — At an age of the world when 
there was probably much more carbonic acid gas in 
the atmosphere than at present, great forests were 
produced, surpassing in all probability anything known 
at the present time even in the tropics. These forests 
in some unknown way, possibly from great tidal waves, 
were buried at depths which prevented decay and at 
the same time brought them under the influence of 
much heat and pressure. The result was that a greater 
or less amount of the volatile matter contained in the 
wood was expelled, and the wood was changed into 
what we now call coal. In cases where the heat was 
slight and only minimum changes took place lignite 
coal remains, often brown in color, very soft, fre- 
quently showing even the woody structure and knots 
of the trees themselves. With more heat and pressure, 
greater changes took place, forming harder grades of 
bituminous coal, but still the product contains much 
volatile matter. It is from this variety of coal that 
coke is made. At still higher temperatures, more of 
the bitumen was expelled with the formation of semi- 
anthracite coal, and then finally, anthracite, having 
no volatile residue at all. Carried still further in ex- 
treme cases the anthracite coal became graphite and 
lastly, in still rarer cases, the diamond. 

The Volatile Portions. — A portion of the volatile 
matter driven off at various stages in the transforma- 
tion of wood into coal was in the form of gas ; much of 
this undoubtedly escaped into the air and ivas lost: 



CARBON AND A FEW COMPOUNDS 149 

some of it was caught below impervious layers of rock 
and there remained until drilled into, when it escaped, 
sometimes with enormous pressure and this is our 
natural gas. Other portions on cooling were liquids 
and form at least a considerable part of our petroleum 
deposits. These natural oils are of two classes; one, 
a paraffin bearing oil and the other an asphalt bearing 
oil. The former are more desirable, as a much greater 
quantity of refined products may be obtained from 
them. In distilling such oils, the portion coming off be- 
low 150° C. is classed as gasoline. This may be frac- 
tionated, however, into several portions, giving us pe- 
troleum ether, rhigolene, benzine, naphtha, and gaso- 
line. Between 150° and 300° kerosene is obtained; and 
above this in successive fractions, heavy burning oils, 
paraffin oil, lubricating oils, vaseline, paraffin, etc. 
Originally, the percentage of gasoline, the most de- 
sirable fraction, in petroleum is not large ; but by a 
process of " cracking' ' different with the different re- 
fining companies, the heavier portions are broken up so 
as to increase greatly the amount of gasoline obtained. 
The asphalt oils after the lighter fractions are removed 
are used in road making, oiling boulevards, sprinkling 
railway tracks to prevent dust, as fuel in engines, and 
various other ways. By many scientists they are sup- 
posed to be of animal origin while the paraffin oils are 
believed to be of vegetable. 

10. Compounds of Carbons. — Carbon Monoxide, CO. — 
Carbon forms two oxides, with one of which we are 
more or less familiar. The other is carbon monoxide. 
It is always formed when carbon is burned in a sup- 
ply of air not sufficient to give complete combustion.. 
It is also formed when carbon dioxide passes over or 



150 CHEMISTRY FOR NURSES 

through red-hot carbon, in which case the carbon takes 
away a part of the oxygen from the dioxide. There 
are several ways in which carbon monoxide finds its way 
into our homes. Most furnaces are made of cast iron: 
at night when banking the fire before retiring, a con- 
siderable amount of cold fuel is thrown in, the draughts 
are closed and the result is the formation of quantities 
of the monoxide. Fig. 29 will make this clear. In the 
lower part of the fire box as the air comes in from the 
ash pit carbon dioxide will be formed; as this flows up 
through the mass of red-hot coal half the oxygen is re- 
moved, thus: 

C0 2 + C->2CO 

Now this passes on up through the fire and under or- 
dinary circumstances meeting air above the fire which 
comes in through the draft in the door would burn 
and produce again the dioxide. This is easily seen in 
an anthracite fire in a furnace or base-burner, in the 
blue lambent flame, playing over the surface. But when 
a layer of cold fuel is present the monoxide is cooled 
below its kindling point and does not burn till the new 
layer has become hot; in the, meantime it is being oc- 
cluded by the red-hot cast iron wall of the fire box and 
transmitted promptly through it to the air chamber on 
the other side, from which it is carried up into the liv- 
ing rooms above. The odor of the gas can be detected 
in such cases very soon after banking the fire. The 
same thing happens in base-burners when much coal is 
shaken down into the fire box. Again, tobacco smoke 
contains a considerable amount of carbon monoxide. 
It is produced as just explained. At first carbon di- 
oxide is formed, then this being drawn back through 



CARBON AND A FEW COMPOUNDS 



151 



the layer of red-hot tobacco is reduced to the monoxide 
and expelled as such into the room. A gas mantle, 
which shows any sign of becoming black from deposit 
of carbon is always producing the monoxide because it 
is not obtaining a plentiful supply of air. Gas heaters 
when burning with a yellow flame instead of blue are 
offending in the same way and for the same reason. 
Likewise, cook-stoves whenever the flame is yellow, 
are not receiving sufficient air to completely burn the 




Fig. 29. — Formation of carbon monoxide in a furnace. 

gas and are producing more or less carbon monoxide. 
Thus it is seen this compound may find its way into our 
living rooms in various ways. 

Banger of Carbon Monoxide. — Carbon monoxide is a 
colorless gas, slightly lighter than air, burns with a 
pale blue flame, has a peculiar faint odor, more or less 
stifling, and very poisonous. It attacks the hemoglobin 
and renders the blood incapable of carrying oxygen, 
hence asphyxiation and death soon follow its continued 
respiration. Numerous cases of suicide are on record 



152 CHEMISTRY FOR NURSES 

where death was secured by covering an open charcoal 
fire with considerable fresh fuel and retiring in the 
same room. Knowing the poisonous character of this 
gas it is important to guard against breathing it. 
Sleeping rooms, warmed by furnace, should have the 
registers closed at night and outside windows opened. 
Gas jets used for lighting or heating should have air 
so regulated as to secure complete combustion and pre- 
vent the formation of the poisonous oxide. 

Carbon Dioxide, C0 2 . — As elsewhere stated carbon 
dioxide constitutes from three to four hundredths of 
one per cent of the air. Its use to plant life has also 
been suggested. It is a colorless gas, not combustible, 
will not permit of the combustion of other substances 
with rare exceptions, is slightly soluble in water, form- 
ing the theoretical; carbonic acid; is about once and a 
half as heavy as air, and not poisonous. 

Uses of Carbon Dioxide. — One of the most familiar 
uses of this gas is in the making of soda water; under 
great pressure the gas is admitted to cold water from 
gas cylinders and is absorbed to a considerable extent. 
As soon, however, as the pressure is removed which 
happens when the soda water is drawn from the faucet, 
the gas begins to escape producing the familiar ef- 
fervescence. It is the dissolved carbon dioxide which 
gives the familiar, biting taste of such water; cider, a 
few days old, effervesces because of the presence of 
carbon dioxide, and owes its sharp taste partly to the 
same cause. 

The common fire extinguisher, seen in the corridors 
of many public buildings, owes its efficiency largely to 
the carbon dioxide generated when put into use. Fig. 
30 will show how it works. The brass container is filled 



CARBON AND A FEW COMPOUNDS 



153 



with water nearly to the top. A pint bottle, with a por- 
celain or lead stopper fitting so loosely that it will 
fall out if inverted, is nearly filled with sulphuric acid; 
in the water is a pound or more of common cooking 
soda. When desired to use, the extinguisher is turned 
upside down ; the acid is emptied into the soda solu- 




Fig. 30. — Babcock fire extinguisher. 

tion and a rapid evolution of carbon dioxide takes 
place, as shown by the equation, 

NaHC0 3 + H 2 S0 4 -> C0 2 + NaHSO, + H 2 



The pressure obtained at the same time throws a vigor- 
ous stream of water and gas on the fire. 

Carbon Tetrachloride, CCl±. — This is not a com- 
pound well known to the public, but it has some uses 



154 CHEMISTRY FOR NURSES 

which render it valuable. It is a fine solvent for oil, 
grease and like substances, is not inflammable, like gas- 
oline, and not very expensive. Hence it may safely be 
employed in the household instead of gasoline for re- 
moving spots from clothing. "Pyrene," a largely ad- 
vertised fire extinguisher consists largely of carbon 
tetrachloride. When thrown upon a fire, it is rapidly 
vaporized, and the vapors being heavy and not com- 
bustible, smother the fire. "Carbona, " another com- 
mercial article advertised for cleaning garments is 
largely this same compound with some benzine present 
but not enough to be inflammable in the presence of 
the heavier liquid. 

Carbides. — There are several binary compounds of 
carbon now assuming considerable commercial impor- 
tance. One of these is calcium carbide, CaC 2 , used in 
the manufacture of acetylene, which will be mentioned 
elsewhere. Calcium carbide is made in electric fur- 
naces at such places as Niagara Falls, where water 
power may be had cheaply. The following equation 
shows the chemical change: 

CaO + 3C^CaC 2 -f CO 

Carborundum, SiC, is made in a similar way by fus- 
ing together sand, Si0 2 , and coke. The equation follows: 

Si0 2 + 3C -> SiC + 2CO 

It is used very extensively as an abrasive. It is 
crushed to a powder, mixed with some cementing ma- 
terial and by hydraulic pressure, made into whetstones, 
wheels for grinding and polishing and for all purposes 
where emery is used. It is much harder than emery, 



CARBON AND A FEW COMPOUNDS 155 

hence cuts faster. It is the hardest of all substances ex- 
cept the diamond and by some it is claimed even to 
surpass the diamond. 

A third, iron carbide, is not an article of commerce, 
but its great value demands a brief notice. When steel 
is made a small amount of the carbon present in the 
iron combines with iron and forms the carbide. It is 
this which gives the hardness to steel and renders pos- 
sible its being- tempered and made into cutting tools. 

Exercises for Review 

1. What are some of the ways in which carbon appears in 
compounds in nature? 

2. Name two allotropic forms of pure, crystallized carbon. 

3. Give proof that the diamond is pure carbon. 

4. Compare the diamond with graphite. 

5. Describe Moissan's method of making diamonds. What 
value has this experiment? 

6. Give several uses of diamonds in a practical way. Upon 
what property do all these uses depend? 

7. What practical uses has graphite? 

8. How is charcoal made now? What by-products are ob- 
tained? 

9. Name two varieties of charcoal: Give special uses of each. 

10. How is coke made? What is main use? 

11. How is coal gas made? Name four by-products obtained. 

12. Name the various products obtained from coal tar. 

13. What is gas carbon? Its two main uses? 

14. How were coals formed? Give three classes of coals. How 
different? 

15. In the formation of coals what two other products formed? 

16. What two kinds of petroleum? Which is the more valu- 
able? Why? 

17. What is meant by " cracking" an oil? 

18. Name the various products obtained from petroleum. 

19. What are some of the ways carbon monoxide gets into 
our homes? 



156 CHEMISTRY FOR NURSES 

20. What danger accompanies the presence of carbon monox- 
ide? 

21. Give characteristics of carbon dioxide. Is it poisonous? 

22. What practical uses has carbon dioxide? Value to plants? 

23. Describe the Babcock fire extinguisher. 

24. Give some valuable uses for carbon tetrachloride. What 
is pyrene? 

25. What is carbona? Uses? . 

26. Name three carbides. How are two of them made? 

27. Give uses of the three carbides named. 



CHAPTER XV 
SOME EVERYDAY CARBON COMPOUNDS 

Outline — 

1. Hydrocarbons, What? 

(a) The Paraffins. 

(b) Methane. 

(c) The Gasoline Series. 

(d) Kerosene. 

2. Hydrocarbon Derivatives. 

(a) Chloroform, Iodoform. 

(b) The Alcohols. 

(c) Organic Acids. 

(d) The Aldehydes. 

(e) Ethers. 

(f) Ethereal Salts. 

(g) Glycerine. 
(h) Edible Fats. 

3. Oleomargarine. 

4. Soaps. 

(a) Method of Manufacture. 

(b) By-product Formed. 

(c) Chemistry of Cleansing. 

5. The Olefines. 

6. Vegetable Oils and Hydrogenation. 

7. The Acetylenes. 

8. Carbohydrates. 

(a) Composition. 

(b) Glucose. 

(c) Sucrose-Cane and Beet Sugar. 

(d) Starch. 
Exercises for Eeview. 

157 



158 CHEMISTRY FOR NURSES 

1. Hydrocarbons. — A hydrocarbon is a compound of 
carbon and hydrogen, as the name indicates. Some- 
where near a hundred thousand hydrocarbons, includ- 
ing compounds derived from them, have been prepared 
and studied. A very few of these are of importance to 
us in everyday life. In a preceding chapter mention 
was made of paraffin — base petroleums and of the large 
number of compounds obtainable from such oils. 
Really all these belong to a single series called the par- 
affins with a very simple relation existing among them. 
The first six of the series are given below although over 
sixty are known: 



Methane, 


CH 4 


Ethane, 


C 2 H 6 


Propane, 


C 3 H 8 


Butane, 


C 4 H 10 


Pentane, 


C 5 H 12 


Hexane, 


C G H 14 



The others of the series receive their names as do the 
fifth and sixth from the Greek numerals corresponding 
to the number of carbon atoms present. Thus, in 
hexane it will be observed there are six carbon atoms 

Methane or Marsh Gas, CH±. — This gas is being pro- 
duced at the bottom of ponds and creeks, wherever 
organic matter, as sticks and leaves, is undergoing de- 
composition. It was largely this produced when coal 
was forming from the buried forests; and the supplies 
of natural gas furnished our cities is about 95 per cent 
marsh gas. It is colorless, almost odorless, a little more 
than half as heavy as air, very inflammable, hence ex- 
plosive when mixed with air. It is this gas, known to 
coal miners under the name of "fire damp" which 



EVERYDAY CARBON COMPOUNDS 159 

causes the explosions in the mines. AVhen the explosion 
takes place as the supply of air is limited, the resulting 
product from the carbon is carbon monoxide, known to 
the miners as "after damp" or "black damp;" it is 
this poisonous gas that usually causes most of the deaths 
in such cases. Incidentally it might be mentioned that 
carbon dioxide by miners is often called "choke damp," 
showing that they recognize the difference between these 
several gases. 

The Gasoline Series. — We have seen that gasoline is 
a mixture of several oils : in reality, it is composed 
mainly of the sixth, seventh, and eighth in this series, 
and the different oils mentioned are simply different 
combinations of these three. Kerosene consists of the 
next eight in the series. It will be seen that each one 
is CH 2 greater than the preceding one : since this close 
relation exists it does not seem strange that the process 
of "cracking" previously mentioned is possible in ob- 
taining an increased amount of gasoline from any sam- 
ple of petroleum. Summing up, then, it will be noticed 
that in this series, all of which are known as paraffins, 
the first five are gases, the next considerable number are 
liquids of constantly increasing boiling point, and those 
higher up are the solid paraffin familiar to all. 

2. Hydrocarbon Derivatives. — A hydrocarbon de- 
rivative is a compound formed by substituting some- 
thing for one or more of the hydrogen atoms in the 
compound. From methane, CH 4 , are derived two very 
familiar compounds, of interest and value, already 
mentioned elsewhere; chloroform, CHC1 3 , and iodo- 
form, CHI 3 . Their use is well known and mentioned 
under chlorine. 

Other Derivatives. — The alcohols may also be re- 



160 CHEMISTRY FOR NURSES 

garded as derivatives of the paraffins, in which hy- 
droxyl, HO, has been substituted for hydrogen. Thus: 

CH 4 would give CH 3 OH, one hydrogen being replaced; 
C 2 H 6 would give C 2 H 5 OH, and so on for the series. 

The first of these is methyl, or wood alcohol, and the 
second is ethyl, or grain alcohol. The first is obtained 
from the distillation of wood in making charcoal and 
the second by the fermentation of grains. Denatured 
alcohol is ethyl alcohol which contains usually about 
10 per cent of some other substance which renders it 
undrinkable and unfit for use in any medicine or food 
product. Sometimes this adulterant is wood alcohol, 
sometimes benzine; the government allows at present 
several modifications so as to adapt the use of a cheap 
solvent to a very large number of practical applica- 
tions. 

Preparation of Alcohol. — As already stated ordinary 
alcohol is made from grain. Before fermentation with 
the production of alcohol can take place, the starch in the 
grain must be changed. This is brought about by the ac- 
tion of an enzyme, diastase. The grain is dampened and 
kept warm until it begins to grow; during this period 
the starch is converted by the enzyme, at least partly, 
into a form of sugar; at the proper stage, the grain is 
dried, which stops the process. It is then crushed or 
ground, yeast is added and the process of fermentation 
goes on with the formation of the alcohol. The steps 
will be shown by the following equations: 

(C 6 H 10 O 5 ) n + nH 2 -* nC 6 H 12 6 

The water is added to the starch through the action of 
the enzyme, diastase, already mentioned. 



EVERYDAY CARBON COMPOUNDS 161 

C 6 H 12 6 -* 2C0 2 + 2C 2 H,OH 

To separate the alcohol from the water it must be dis- 
tilled. This has to be done several times, for while the 
boiling point of alcohol is about 78° C. and that of 
water 100° still considerable water comes over with 
the alcohol. That usually put upon the market is 
about 95 or 96 per cent pure. To obtain absolute 
alcohol this commercial article is treated with lime or 
anhydrous copper sulphate and allowed to stand 24 
to 48 hours until the water has been absorbed and then 
separated and distilled. 

Organic Acids. — These are derived from the alcohols 
by oxidation. Thus, 

Methyl Alcohol, CH 3 OH + 2 -> HCOOH + H 2 
Ethyl Alcohol, C 2 H 5 OH + 2 -> CH 3 COOH + H 2 

It will be noticed that two of the hydrogen atoms in 
the alcohol have been oxidized to form water and also 
an atom of oxygen added to the alcohol molecule. 
Every organic acid contains the group COOH and their 
formulas are written so that we may recognize an acid 
at once by the formula. The first of those just above is 
known as formic acid, from the Latin name, forma, 
meaning an ant ; it was so named because it is secreted 
by certain species of ants and its odor may be readily 
detected upon disturbing an ant hill. It is also secreted 
by wasps and bees and similar stinging insects, and it 
is this which causes the pain when injected into the 
tiny wound produced by the stinger. Being acid in 
character, therefore, the natural antidote is an alkali, 
and common soda being always accessible, serves the 
purpose well. 



162 CHEMISTRY FOR NURSES 



Acetic Acid. — This acid in dilute form is familiar to 
every one as vinegar, which runs from 3 to 5 per cent 
acid. Formerly it was made largely from cider: the 
apple juice contains grape sugar, which undergoes, first 
a vinous, that is, alcoholic fermentation, as has been 
seen in the second step of the preparation of grain 
alcohol: then, another germ also found in the air, 
causes a second change whereby the alcohol is oxidized 
to vinegar. Pure acetic acid is a colorless liquid which 
solidifies at 16.7° C. and boils at 119°. Such acid is 
known as glacial acetic. It has a sharp, penetrating 
odor, more or less irritating. 

The present demand for acetic acid is so great that 
only a small percentage comes from the fermentation 
of cider. The distillation of wood in making charcoal 
furnishes a considerable amount, but probably the 
greater proportion is made from glucose which is 
largely obtained from cornstarch. By means of a di- 
lute acid the starch is converted into glucose and the 
acid is then carefully neutralized and removed. The 
glucose then is slowly passed through tanks, contain- 
ing shavings which have been inoculated with the 
"mother of vinegar/' Mycoderma aceti, the germ which 
produces the fermentation, and the oxidation rapidly 
takes place. It is made cheaply this way, and if vine- 
gar is a wholesome article of diet at all, is far prefer- 
able to that made from cider. The latter frequently 
contains besides considerable portions of decomposed 
organic matter, numerous vinegar eels, tiny white 
worms which may be seen on close inspection. Vinegar 
made from glucose may be colorless or of the usual 
brown color due to small portions of carmel added for 
the purpose. 







EVERYDAY CARBON COMPOUNDS 163 

Aldehydes. — There is only one, formaldehyde, in 
which we are interested. But there are a number of 
them, all derived at least theoretically from the 
alcohols by oxidation carried only half as far as in the 
case of the acids. That is, when the oxidation takes 
place, two hydrogen atoms are removed from the 
alcohol molecule with the formation of water, but no 
oxygen is added, as was the case with the acids. Thus: 

2CH 3 OH + 20 2 -» 2HCOOH + 2H 2 Formic Acid pro- 
duced 

2CH 3 OH + 2 -^2HCOH + 2H 2 Formic Aldehyde pro- 
duced 

2C 2 H 5 OH + 20 2 -> 2CH3COOH + 2H 2 Acetic Acid 
formed 

2C 2 H 5 OH + 2 -> 2CH3COH + 2H 2 Acetic Aldehyde 
formed 

Formic Aldehyde. — Formic aldehyde is a gas at or- 
dinary temperatures but may be liquefied at a tem- 
perature of -21° C. Formalin, the commercial article, 
is a 40 per cent solution of formaldehyde in water. The 
gas has a peculiar, irritating odor, affecting especially 
the eyes and nostrils. It is strongly germicidal and two 
or three drops in a glass of water serve excellently as a 
mouth or throat wash. It should not be swallowed. It 
is used extensively as a preservative for zoologic and 
anatomic specimens, being much better than alcohol. It 
hardens the tissues and puts them into much better con- 
dition for making microscopic examinations if such are 
desired. It is also largely used as a disinfectant in case 
of epidemics of contagious diseases, in that it is not ex- 
pensive and is easy of application. This is often done 



164 CHEMISTRY FOR NURSES 

by pouring on lime. The heat generated drives the gas 
out quickly. 

Ethers. — There is a series of ethers corresponding to 
the alcohols. Ethers are really oxides of organic radi- 
cals or hydrocarbon groups. Thus: 



2CH 3 OH-^(CH 3 ) 2 + H 2 Methyl Ether 
2C 2 E 5 OH^(C 2 H 5 ) 2 + H 2 Ethyl Ether 



It is only the second one in the series in which we are 
interested. It will be observed that they obtain their 
names from the alcohols from which they are derived. 
Ethyl ether, or as it is often called, "sulphuric ether, " 
because sulphuric acid is used in the manufacture of it, 
is a colorless liquid, with a rather pleasant, sweet odor ; 
it is very volatile, having a boiling point of 34.9° C. 
which is below the temperature of the human body. It 
is an excellent solvent for iodine, and various organic 
substances, such as oils, and fats. It is commonly used 
as an anesthetic, but on account of its inflammability 
which is even greater than that of gasoline, it is danger- 
ous in the presence of any open flame. In common prac- 
tice probably more often chloroform and ether are used 
mixed. 

Esters or Ethereal Salts. — Just as the mineral acids 
and bases may combine to form salts, which we have al- 
ready studied, so the organic or carbon acids and bases 
may. It must be noted that the organic bases or hy- 
droxides we call alcohols. If acetic acid and ethyl al- 
cohol are put together and w r armed gentty a very agree- 
able fruity odor is obtained due to the ethyl acetate 
formed. This acetate is an ethereal salt and the action 
is shown in the equation 



, 



EVERYDAY CARBOX COMPOUNDS 165 

C 2 H 5 OH + CH3COOH -* C 2 H 5 CH 3 COO + H 2 

It will be noticed that water is one of the products 
formed here as it was with the mineral acids. The word, 
ester, is derived from the two words, ethereal salts, and 
has no special meaning in itself. The esters are of in- 
terest from the fact that the artificial extracts of apple, 
pear, banana, etc., found at the groceries and in the 
sirups of the soda fountains belong to this class of 
compounds. Thus : 

Ethyl Butyrate, Artificial Pineapple 
Amyl Valerate, Apple 

Isoamyl Acetate, " Pear 

The glyceryl esters will be mentioned later. 

Glycerine, C s H^(OH) 3 . — It will be observed from the 
formula for glycerine that it is an alcohol containing 
three hydroxyl groups. It is a by-product of the soap 
factories; formerly it was left in the soap, but on ac- 
count of its great commercial value it is now separated 
except in few cases where a special soap is desired. It 
is a thick, sirupy liquid, with a sweet taste, named for 
this reason from the Greek word for sweet. It is very 
soluble in water and is hygroscopic. On this account 
when the price admits, it is sometimes added by bakers 
to cakes to keep them moist. The chief use for glycer- 
ine is for the manufacture of explosives as already de- 
scribed. 

Glyceryl Salts. — As glycerine, or more properly called, 
glycerol, is an alcohol or organic base, it forms salts, or 
esters. Many of these are of extreme value, as they are 
the ordinary oils and fats used for food. Thus, butter, 



166 CHEMISTRY FOR NURSES 

olive oil, cottonseed oil, beef fat, lard, etc., are all 
glyceryl salts. 

Butyrin— C 3 H 5 (C 3 H 7 COO) 3 — Glyceryl Butyrate 
Palmitin— C 3 H 5 (C 15 H 31 COO) 3 — Glyceryl Palmitate 
Stearin— C 3 H 5 (G 17 H 35 COO) 3 — Glyceryl Stearate 
Olein— C 3 H 5 ( C 17 H 33 COO ) 3 — Glyceryl Oleate 

The ordinary edible fats such as those of beef, pork 
and mutton, are mixtures of the last three named 
above. The greater the proportion of stearin present, 
the higher the melting point, while an excess of olein 
gives a fat easier to melt, hence softer in warm weather. 
Common lard contains about 60 per cent olein and 40 
per cent of the other two. Butter is a mixture of all 
four of the above, containing w T hen free from water, 
about 8 per cent of butyrin. Olive oil, a liquid at or- 
dinary temperatures, is about three fourths olein. 
"Mazola" an oil made from corn as a by-product in 
the manufacture of glucose, and cottonseed oil are not 
specially different in composition. 

3. Oleomargarine. — At the present time there is a 
very large variety of these artificial butters being offered 
on the market. Most of them are mixed animal and 
vegetable fats and oils, though several entirely vege- 
table are now to be had. All the better grades are prob- 
ably good, are as wholesome, and as nourishing as real 
butter and may well be used instead. It is largely sen- 
timent merely that prevents their use, and no good 
reason. Three formulas for manufacture of three dif- 
ferent grades as used by one of the large packing 
houses are given below: 



EVERYDAY CARBON COMPOUNDS 167 

Formula No. 1. 

Neutral Lard 75 pounds 

Peanut Oil 75 ' ' 

Cottonseed Oil 175 " 

Oleo Oil .675 " 

Skim Milk 60 gallons 

These are put together and churned, the milk being used to 
give more of the flavor of real butter. There are then added: 

Creamery Butter 150 pounds 

Salt 125 " 

Total weight 1275 " 

This does not include the water which is taken up in the 
churning and later process of working the butterine. The water 
may run as high as 12 to 14 per cent. 

Formula No. 2. 

Neutral Lard. 50 pounds 

Peanut Oil 225 " 

Cocoanut Oil 50 " 

Oleo Oil 675 " 

Skim Milk 60 gallons 

Salt 125 pounds 

Weight 1125 pounds 

The process is the same as in the preceding. 

Formula No. 3. 

Neutral Lard. 50 pounds 

Peanut Oil 100 " 

Cottonseed Oil 125 " 

Oleo Oil, 725 " 

Butter 400 " 

Skim Milk 60 gallons 

Salt 125 pounds 

Weight 1575 " 

Method pursued is same as above. 



168 CHEMISTRY FOR NURSES 

Some of the nut oleos now being introduced contain 
more of the glyceryl butyrate than the animal oleos and 
more nearly resemble real butter in taste on that ac- 
count. Their chief objection seems to be in the lower 
melting point, which makes them more difficult of 
handling in hot weather. But they are a wholesome 
and nutritious article of food. It may be of interest to 
know how greatly the use of vegetable fats has been 
increasing in late years. Government reports show that 
in 1914 cocoanut oil, which is used mainly for the manu- 
facture of nut oleos, was imported to the amount of 
seventy-four million pounds, while in the present year, 
1918, it has amounted to 259 million pounds. Peanut 
oil increased in amount from one million gallons in 
1914 to over eight million, and peanuts from 18 million 
pounds to 76 million. Soy bean oil in 1914 was imported 
to the amount of 16 million pounds, while this year it 
was 337 million. 

4. Soap Making — Saponification. — The art of soap 
making has been known for centuries but for many 
years soap was used merely as a pharmaceutic prepara- 
tion and not as a detergent, hence made on a very small 
scale. Now it is one of the great industries of the 
world. It is prepared by the union of caustic soda or 
potash with some fat or oil. As organic compounds re- 
act slowly, the mixture must be kept at the boiling 
point for several days during which time the following 
reaction takes place: 

3NaHO + C 3 H 5 (C 17 H 35 COO)3 -» 3NaC 17 H 35 COO + C 3 H,(HO) 3 

The reaction has shown only stearin but of course fats 
being mixtures of several esters the soap formed would 
likewise be a mixture. It will be noticed that glycerol 



EVERYDAY CARBON COMPOUNDS 169 

is the by-product formed. If potassium hydroxide is 
used instead of sodium hydroxide the product is a soft 
soap, which remains as a soft pasty mass and the 
glycerine is not separated out. Some years ago farmers 
made about all the soap they used, especially for laun- 
dry purposes, from the wood ashes obtained in the 
winter from their stoves. Sometimes they made this 
soft soap which wood ashes give into hard soap by ad- 
ding salt to the finished product. The hard soap then 
separates out, rises to the top and when cold may be 
lifted off and cut into cakes. 

KC 17 H 35 COO + NaCl -> NaC 17 H 35 COO + KC1 

How Soap Cleanses. — There seems considerable doubt 
as to the action of soap in removing dirt from an object. 
As a rule foreign matter which Ave call "dirt" is held 
to the body or to articles of clothing largely through 
oily matter. If this can be removed the dirt is carried 
away mechanically by the water or whatever the liquid 
may be. When gasoline or carbon tetrachloride is used 
there is no question about the action. The grease is 
simply dissolved; then there is nothing to hold the for- 
eign matter and it is removed. It is believed now that 
when soap is used an emulsion is formed by it and the 
oil and that then the water removes the dirt. 

5. The defines. — With one exception the compounds 
Ave haA^e just been studying may be regarded as de- 
riA^atiA es of the paraffins. There is another class of hy- 
drocarbons known as the olefines, the loAvest in the 
series of Avhich is ethylene, Avith a formula of C 2 H 4 . 
The first six of them are: 



170 CHEMISTRY FOR NURSES 



C 2 H 4 


Ethylene 


C 3 H 6 


Propylene 


C 4 H 8 


Butylene 


C 5 H 10 


Pentylene or Amylene 


C 6 H 12 


Hexylene 



These are all what are called unsaturated compounds 
as explained in the chapter on Valence. If we express 
this by a graphic formula which is an attempt to show 
exactly how the various atoms are linked together, it is 
thus: 

H 



Methane, CH 4 


H— C— H 

i 




1 
H 




H H 

I i 


Ethane, C 2 H G H- 


-C— C— H 




H H 




H H 

1 1 


Ethylene, C 2 H 4 


1 1 

_C— C— 

1 1 




H H 




H H H 

I I I 


Propylene, C 3 H 6 


1 1 1 
_C— C— C- 
1 1 1 




1 1 
H H H 



By examining these formulas it will be seen that in the 
paraffins all the "bonds" of the carbon atom are in 
use, or are saturated: in the olefines, there are two 



EVERYDAY CARBON COMPOUNDS 171 

bonds in each case not in use. There is abundant ex- 
perimental evidence that such is true, because we can 
readily cause all these compounds to take up other 
atoms or groups, and always to the number of the un- 
used bonds. This leads to some very interesting pos- 
sibilities which will be mentioned later. About the 
only other item of importance in connection with the 
olefmes is the fact that the first is a constituent of com- 
mon coal gas, and gives the yellow color to the flame 
when burned in an ordinary jet. 

6. Unsaturated Oils. — It was said in a preceding sec- 
tion that fats containing a high percentage of olein are 
lower in melting point than those with a small amount 
of the same compound. This is because olein is itself 
a liquid at ordinary temperatures. By referring to the 
formulas it will be seen that the amount of hydrogen 
is proportionately less in olein than in the others, that 
is, it is an unsaturated compound. Eepresenting this 
graphically, without trying to show the whole mole- 
cule, stearin would be thus: 

H H 

I I II 
Carbon chain — C— C— C— 0— (C 3 H 5 ) = 

H H 

in which the first part consists of a chain of seventeen 
carbon atoms all with hydrogen attached to saturation. 
Olein would be thus: 

H HO 

I • I I II 
Carbon chain — C— C— C— C— 0— (C 8 H 5 ) = 

H H 



172 CHEMISTRY FOR NURSES 

which shows one carbon atom with no hydrogens at- 
tached. It is possible, using some catalytic agent, more 
often nickel, to cause such unsaturated oils as this to 
take up this additional amount of hydrogen. The 
process is called hydrogenation, and is of very great 
commercial value. "Crisco" and various other fats 
used in cooking which are rapidly taking the place of 
lard are vegetable oils which have thus been hydro- 
genated or saturated with hydrogen. Before treat- 
ment they are yellow oils: afterwards, they are white 
solids. They are no more wholesome in the solid form, 
but the public is accustomed to solid fats instead of 
oils in cooking and hence the change makes them more 
salable. In the same way the oils of the soy bean, cot- 
ton seed, cocoanut, peanut, corn, etc., are being hy- 
drogenated and converted into white solids. The various 
compound lards on the market as well as "Cottolene," 
" Cottosuet, ' ' "White Cloud/ ' etc., are all preparations 
containing a greater or less amount of vegetable oils. 

7. The Acetylenes, — A third class of hydrocarbons 
exists, known as the acetylenes. There is only one of 
any importance to us and that is the first in the series, 
known as acetylene, with a formula of C 2 H 2 . It is 
prepared by the treatment of calcium carbide with 
water, thus: 

CaC 2 + 2H 2 -* C 2 H 2 + Ca(HO) 2 

Acetylene is a valuable illuminating gas and is used 
extensively in suburban lighting and in the oxy- 
acetylene welding. For this last purpose it is burned 
in a blowtorch similar to the oxyhydrogen blowpipe 
and gives a temperature not essentially different from 



EVERYDAY CARBON COMPOUNDS 173 

the other. With it rods of iron or steel are easily 
melted in the open air, iron plates are melted in two 
and various other similar operations performed. 

8. The Carbohydrates. — In this chapter up to this 
time we have been studying the hydrocarbons and their 
derivatives. There is another class of carbon compounds 
of great importance, the carbohydrates. They contain 
oxygen in addition to the carbon and hydrogen and in 
proportions such as to form with the hydrogen a cer- 
tain number of molecules of water. Thus, typical of 
three classes of carbohydrates, we may name 

Glucose, C 6 H 12 6 
Cane Sugar, C 12 H 22 1:L 
Starch, (C 6 H 10 O 5 ) n 

which are typical of the three classes, mono-, di-, and 
poly-saccharids. In all these it will be observed that 
the hydrogen is double the amount of the oxygen. If 
we heat them strongly, the hydrogen and oxygen are 
expelled in the form of water, leaving a black mass of 
charcoal. 

Glucose, as already mentioned, is manufactured from 
cornstarch after the oil has been removed from the 
grain. By the action of dilute sulphuric acid upon the 
starch it is made to take up another molecule of water 
for each group and is thus changed into sugar. It is 
about three-fifths as sweet as cane sugar. Usually, how- 
ever, it is put on the market in the form of sirups, often 
under the name of "corn sirup." Naturally it is of a 
golden brown color, but it is sometimes bleached by 
means of sulphur dioxide. The colorless brand of 
"Karo" has been bleached in this way. While there is 



174 CHEMISTRY FOR NURSES 

probably no objection to bleaching it, nothing is added 
to the value. There hasi been a popular prejudice 
against the use of glucose because of a hazy knowledge 
that sulphuric acid is used in the manufacture. This 
prejudice is altogether unfounded, for the acid is 
simply catalytic in its action, takes no part in the chem- 
ical change whatsoever and is all removed at the close 
of the process. The bleaching sometimes leaves traces 
of the sulphur gas but in the unbleached variety no 
sulphur acids will be found. Besides entering into 
most of the sirups on the market, glucose is commonly 
used now in making much of the candy found in the 
confectionery shops. The fact that it is used in the 
manufacture of vinegar has been mentioned elsewhere. 
Cane Sugar. — Cane sugar and beet sugar have the 
same formula, the only difference being in their source. 
Milk sugar differs only in containing an additional 
molecule of water, really as water of combination, thus: 
C 12 H 22 11 + H 2 0. It is this sugar decomposing in the 
milk that produces the lactic acid, thus changing the 
soluble casein into the insoluble form. 

Starch (C 6 H 10 O 5 ) n . — Cellulose has the same formula 
as starch. It is unknown how many of these groups 
represented in the formula constitute the molecule. 
When starch is converted into glucose as already seen 
the catalytic agent simply causes the addition of water. 
From the fact that cellulose has the same composition 
it should seem possible to make sugar from sawdust or 
worn-out linen. Such a thing is possible but no proc- 
ess has been discovered yet whereby it may be done 
economically. The cellulose molecule, containing prob- 
ably a greater number of carbohydrate groups, is more 
difficult to change. 






EVERYDAY CARBON COMPOUNDS 175 

Exercises for Review 

1. What is a hydrocarbon? Name five. What are they called? 
Why? 

2. What is marsh gas? Why so called? What is fire damp? 

3. What is choke damp? After damp? 

4. What hydrocarbons constitute gasoline? 

5. What constitute kerosene? 

6. What are chloroform and iodoform derived from? 

7. What is a derivative? Illustrate. 

8. Show how the alcohols may be regarded as derivatives of 
the paraffins. 

9. What is denatured alcohol? Why made? Ethyl alcohol? 
Source? 

10. How is grain alcohol made? Wood alcohol? 

11. How is acetic acid derived from alcohol? Where is 
formic acid found in nature? Its antidote? 

12. How is vinegar made mostly? What is glacial acetic 
acid? 

13. How is formaldehyde obtained? What is formalin? 

14. Describe formaldehyde? Give uses. 

15. What ether is of interest in medicine? Why? What are 
ethers? 

16. What is an ethereal salt? What other name for them? 
Name some. 

17. To what class of compounds does glycerine belong? 

18. Source of glycerol? What is its chief use? 

19. Name four glycerol esters. What is butter? What is 
mazola? 

20. What is oleomargarine? Give composition of a typical 
case. 

21. How is soap made? Its by-product? What is soft soap? 

22. What is the process of cleansing by soap? 

23. Compare the olefines with the paraffins and state differ- 
ence. 

24. What is an unsaturated compound? What are olefines? 

25. What is meant by hydrogenation? What effect does it 
have on an oil? 



176 CHEMISTRY FOR NURSES 

26. Name some hydrogenated fats. 

27. How is acetylene made? Its use? 

28. What is a carbohydrate? Name three. 

29. How is glucose manufactured? What is corn sirup? 

30. What is the purpose of the sulphuric acid in making glu- 
cose? 

31. Compare cane, beet and milk sugar. 

32. Compare starch and cellulose. 



CHAPTER XVI 
SULPHUR AND COMPOUNDS 

Outline — 

1. Old Ideas About Sulphur. 

2. Occurrence in Xature. 

(a) In Sicily. 

(b) In United States. 

(c) Method of Obtaining. 

3. Purification. 

•i. Forms of Sulphur. 

(a) Yellow — Flowers. 

Brimstone. 

Crystals, Two Varieties. 

(b) Amorphous. 

5. Properties of Sulphur. 

6. Uses of Sulphur. 

7. Compounds of Sulphur. 

(a) Sulphides. 

(b) Oxides. 

Preparation. 

Characteristics. 

Uses. 

(c) Acids. 

Sulphuric. 

Manufacture, Two Processes. 

Characteristics. 

Uses. 
Sulphurous. 
Fuming Sulphuric. 
Thiosulphuric. 
(d) Sodium Thiosulphate. 
Uses. 
Exercises for Eeview. 

177 



178 



CHEMISTRY FOR NURSES 



1. Historical. — Sulphur, from the fact that it often 
occurs free in nature, has been known for centuries. 
As stated elsewhere it was at one time regarded as a 
constituent of all metals, also as one of the few sub- 
stances composing the human body. 

2. Occurre'rice in Nature. — The oldest known deposits 
of sulphur are probably those of Sicily w T hich still fur- 
nish a very large amount. Undoubtedly it is being dis- 
tilled by the volcanic heat in that island all the time 
from compounds of sulphur at a greater or less depth 



molten sulphur, 
air, and water 



water 
temp. 170° 



^ 



> 



■^ 



ii ii b 



i it 
Hi 
I' I 

I 1 i 
I' I 
|I|M 

I,!"' 



Fig. 31. — Method of obtaining sulphur in Louisiana. 



compressed 
air 



in the earth so that the supply is constantly being re- 
newed. Near the western entrance of Yellowstone 
Park the Sulphur Mountains consist largely of an im- 
pure sulphur which will be developed when the demand 
justifies it. At the present time most of the supply of 
sulphur used in the United States is obtained from 
Louisiana, at a place called Sulphur. It is said that 
one well there furnishes five hundred tons daily and 
that the total output is between twenty and twenty- 
five thousand tons a month. The deposit is at a depth 



SULPHUR AND COMPOUNDS 179 

of 900 feet below the surface. To obtain it a method 
somewhat similar to the production of salt is used. A 
hole several inches in diameter is drilled down to the 
sulphur deposit. In this are sunk four pipes, one within 
the other as shown in Fig. 31. The two outer ones carry 
down water heated under pressure to about 170° C. 
which is more than sufficient to melt the sulphur: com- 
pressed air is forced down the smallest of the pipes and 
this forces up through the second pipe the mixture of 
air, water and molten sulphur. It flows into large bins, 
about 150 by 250 feet, where the sulphur solidifies and 
the water runs off. The purity is such that no refining 
at all is necessary for all ordinary uses. When desired 
for shipment the solid mass is broken by blasting pow- 
der and it is then loaded into cars. 

3. Purification. — If desired for medical purposes some 
further purification may be necessary. This is done by 
heating the sulphur in iron retorts to its boiling point 
and condensing the vapors in a cool chamber. Usually 
one distillation is sufficient. For some purposes this 
product is washed with water and dried before further 
use. 

4. Forms of Sulphur. — Although oxygen is a gas and 
sulphur a solid at ordinary temperatures, they belong 
to the same family of elements. We have seen that 
oxygen occurs in two forms, the ordinary and ozone, 
its allotrope. In the same way sulphur occurs in more 
than one form, yellow and amorphous. There are three 
or four varieties of the yellow: flowers, brimstone or 
roll, and two forms of crystals, rhombic (octahedral) 
and monoclinic (needle-like). Flowers of sulphur is 
obtained when sulphur is boiled and the vapors con- 
densed, as mentioned in purifying it for medicinal pur- 
poses; if the flowers is melted and poured into moulds 



180 CHEMISTRY FOR NURSES 

it is known as brimstone; while the two crystalline 
forms are obtained by two different methods. Sulphur 
dissolves readily in carbon disulphide: if this solution 
is permitted to evaporate slowly the octahedral crys- 
tals are formed, which are the stable variety. When 
found in nature as they often are they are always of 
this system. Beautiful crystals may be obtained in 
the laboratory by making a solution of sulphur in car- 
bon disulphide in a beaker and tying tightly over it 
two thicknesses of filter paper. This causes a slow evap- 
oration of the liquid and a growth of crystals of 
considerable size. (See Fig. 32.) 

Monoclinic Sulphur. — The needle-shaped crystals may 
be made by carefully melting sulphur, not allowing it 







Fig. 32. — Sulphur crystals. 

to become heated much above its melting point, and 
pouring upon a filter paper in a glass funnel. Sufficient 
sulphur should be used to fill the funnel at least half 
full. As soon as the crystals, which can be seen form- 
ing rapidly after the process begins, have nearly cov- 
ered the surface, the funnel should be inverted and the 
portion still liquid poured out. The long, needle-like 
crystals, w T hich have grown out from the sides can then 
be readily seen. They are not a very stable variety 
and eventually break up into the rhombic form. 

Plastic or Amorphous Sulphur. — If sulphur is heated 
to 250° C. and then cooled suddenly by pouring into 
cold water, it becomes a dark, nearly black, solid, soft 



SULPHUR AND COMPOUNDS 181 

like rubber, which may be stretched out with ease. 
In making the experiment it is well to heat the tube 
containing the sulphur until boiling begins, otherwise, 
Ave may not have reached the necessary temperature. 
This form is very unstable. Left in the air, in a few 
days it loses its dark color and has begun a slow change 
back to the yellow variety. At room temperatures, 
however, it requires months and some say even years 
for the transformation to be complete. If kept at the 
temperature of boiling water an hour is sufficient to 
effect the complete change. 

5. Properties of Sulphur. — The yellow varieties of 
sulphur have a melting point of 114.5° C. At this tem- 
perature and a little above, the liquid is a pale yellow 
color, thin, almost as water: as the temperature rises, 
the liquid becomes darker in color and thicker until 
160° C. is reached when it is decidedly viscous and can 
not even be poured from the test tube. Again as the 
temperature rises it becomes thin and at 448° begins 
to boil. The rhombic variety has a density just a little 
more than twice that of water. The yellow varieties 
are all readily soluble in carbon disulphide, the amor- 
phous not. None of them is soluble in water and all 
are without taste or odor. 

6. Uses of Sulphur. — There was a time when a mix- 
ture of sulphur and molasses was regarded as almost 
a necessity in the spring as a tonic. It is still used in 
salves somewhat for its germicidal properties. Boiled 
with lime it is extensively used by horticulturists now 
as a spray on peach, plum and other trees to prevent 
dry rot and destroy other fungous diseases. It is also 
used extensively in the manufacture of rubber goods. 
Without the sulphur, rubber becomes unduly soft in 



182 CHEMISTRY FOR NURSES 

warm weather and very hard and brittle in cold ; sul- 
phur prevents this, through some change not under- 
stood. With a larger amount of sulphur and a higher 
temperature out of contact with the air, the rubber be- 
comes hard and brittle and is known as vulcanite. In 
this form it is used extensively for making combs, elec- 
trical insulators, telephone mouthpieces and receivers, 
phonograph records, plates for false teeth, fountain 
pens and a large variety of other things. The black 
color in most of these articles is caused by the admix- 
ture of small amounts of lampblack. If a pink color 
is desired, vermilion is added. Vulcanite may be made 
to resemble tortoise shell and is sometimes sold in imita- 
tion of the real article. Considerable quantities of 
sulphur are used in the preparation of sulphur dioxide, 
for purposes which will be given under another topic. 

7. Compounds of Sulphur. — Stdphides. — It has been 
mentioned that sulphur and oxygen belong to the same 
family of elements. We have seen that oxygen com- 
bines with all other of the commoner elements except 
fluorine: likewise sulphur combines with a very large 
number of the elements and being negative, with all 
metals except gold and platinum. With many of these 
the action may be made to take place in a test tube, by 
mixing the filings of the metal with sulphur intimately 
and heating strongly. As the chemical action proceeds 
a bright red glow passes through the mass. In nature 
nearly all metals are found in combination with sulphur 
as sulphides and they form many of the common ores 
from which the metals are obtained. 

Hydrogen Sulphide, H 2 S. — This is a gaseous com- 
pound often found dissolved in spring and artesian 
waters. It is supposed to have therapeutic values though 



SULPHUR AND COMPOUNDS 183 

that is very doubtful. It is a colorless gas, of intensely 
offensive, nauseating odor, like that of rotten eggs, 
which give off this gas in abundance ; considerably 
soluble in water, will burn with a pale blue flame, 
which will deposit the sulphur upon a cold dish held 
close up against the flame: burning freely in the air it 
produces steam and sulphur dioxide, the latter of 
which may be recognized by its suffocating odor. It is 
very poisonous, producing dizziness, unconsciousness 
and ultimately death. However, less than one-half of 
one per cent in the air is not attended by serious re- 
sults; as its odor is so intense, the most minute portions 
warn of its presence, hence there need be no reason for 
uneasiness regarding it. The best antidote is very di- 
lute chlorine which may be obtained by adding a little 
hydrochloric acid to a bleaching powder solution. 

Uses of Hydrogen Sulphide. — To the analytic chemist 
hydrogen sulphide is indispensable. It is his means of 
precipitating a very large number of metals and fur- 
nishes the basis for their separation into groups and 
subsequent identification. When using it, precautions 
should always be taken to furnish means of carrying 
off the portions escaping from the liquid. For this use, 
it is generally prepared by treating ferrous sulphide 
with either dilute sulphuric or hydrochloric acid. The 
reaction is given below: 

FeS + H 2 S0 4 -> FeS0 4 + H 2 S 
FeS + 2HC1 -> FeCl 2 + H 2 S 

When hydrogen sulphide burns the reaction is 

2H,S + 30, -* 2EL0 + 2S0 2 



184 CHEMISTRY FOR NURSES 

Oxides of Sulphur. — There are two oxides of sulphur , 
the dioxide with formula, S0 2 and the trioxide, S0 3 . 
The first is always obtained when sulphur is burned in 
the air or when most sulphides are heated strongly 
under like circumstances. 

Sulphur Dioxide. — When this compound is desired for 
experimental work in the laboratory it is generally ob- 
tained by heating concentrated sulphuric acid with 
either copper turnings or with charcoal. We have seen 
that zinc with dilute sulphuric acid sets free hydrogen 
from the acid, but by referring to the order of the met- 
als as regards electropositive character, shown on page 
40 it will be seen that copper is less positive than hy- 
drogen, hence could not set free the hydrogen. It will 
be found that concentrated acids act differently from 
diluted ones; so Avhile sulphuric acid will not set free 
its hydrogen when put with copper, when concentrated 
and hot it will give up part of its oxygen. This is what 
happens: 

H 2 S0 4 + Cu -* CuO + H 2 S0 3 
H 2 S0 3 -> H 2 + S0 2 

H 2 S0 3 is sulphurous acid and is very unstable, hence 
the second reaction given above rapidly follows the first. 
A third reaction follows in which the copper oxide 
formed is dissolved by other portions of sulphuric acid 
present, thus: 

CuO + H 2 S0 4 -> CuS0 4 + H 2 

So, our final products are sulphur dioxide, copper sul- 
phate and water, 



SULPHUR AND COMPOUNDS 185 

Characteristics of Sulphur Dioxide. — Sulphur dioxide 
is a colorless gas, very soluble in water, so much so that 
it must be collected by downward displacement in the 
laboratory and not over water. It is of very irritating, 
suffocating odor; will not burn, or permit of the com- 
bustion of other substances; is acidic in character; 
strongly germicidal and a slow bleaching agent. 

Uses of Sulphur Dioxide. — It has been used exten- 
sively for fumigating buildings: this has generally been 
accomplished by burning in the various rooms or at 
some place where the ventilating system would carry 
the gas to all the rooms, sulphur candles. As formal- 
dehyde may be had so much more quickly and is prob- 
ably much more effective, it is rapidly displacing sul- 
phur dioxide as a fumigating agent. It is used exten- 
sively for bleaching fruits and some other food 
products, as already mentioned in the case of many 
sirups on the markets. At most of the larger grocery 
stores may be found dried apples, in flat annular slices 
nearly white in color. It is well known that when an 
apple or most any other fruit is cut and exposed to the 
air, it turns brown. In drying fruit by artificial heat 
in evaporators, as is done in many places, as often as 
fresh trays of fruit are put into the evaporator small 
quantities of sulphur are placed in a cup on the fur- 
nace, where the sulphur catches fire and burns. The 
dioxide produced, prevents the formation of the brown 
color, until the fresh fruit has been seared over on the 
surface, after which it remains white. In sections of 
our country where rain does not fall in the fruit sea- 
son the drying is done in the open air. To prevent the 
attack of the fruit by various insects it is found neces- 
sary to "sulphur" the fresh fruit. It is cut, spread 
upon galvanized wire trays, and placed in a chamber 



186 CHEMISTRY FOR NURSES 

into which are passed sulphur dioxide fumes. At the 
end of a certain length of time it is removed and placed 
in the open air to dry. Small portions of the sulphur 
are left in the fruit in the form of sulphites, mostly, 
but as there seems no other way to prevent the destruc- 
tive attacks of insects the government has not for- 
bidden the use. It is probable that the amount of sul- 
phite is so small as not to be injurious. 

Uses in Bleaching. — We have already seen that chlo- 
rine and hydrogen peroxide are used for bleaching. 
For certain substances as wool, silks and straws, most 
of which are slightly yellow in nature, chlorine is not 
suited at all, because it would be utterly destructive. 
Hydrogen dioxide is better for some of these, but not 
as desirable as sulphur dioxide. It will be remembered 
that the other agents accomplish the bleaching through 
the oxygen which is set free : sulphur dioxide is believed 
to work in just the opposite manner, that is, by deoxida- 
tion, or reduction. It has the power of removing oxygen 
from other substances because of the fact that it is an 
unsaturated compound. Whether it removes the oxygen 
from the coloring matter in the natural substance or 
reduces it in some other way Ave are not sure; but at 
any rate the reducing action produces a colorless com- 
pound. It is noticed, however, that straws, woolens 
and silks, as they are used and exposed to sunlight 
and air all become yellow again. This is believed to be 
due to the effect of the oxygen of the air in changing 
the compound back again to the condition before it 
was bleached. 

Acids of Sulphur. — There are several acids of sul- 
phur known to chemists but only one of very great 
importance commercially. That is sulphuric, Sulphu- 



SULPHUR AND COMPOUNDS 187 

rous acid, H 2 S0 3 , has been mentioned as a very unstable 
body, hence is not an article of commerce. Its anhy- 
dride, sulphur dioxide, since it is easily liquefied, may 
be purchased in heavy glass siphon bottles. 

Sulphuric Acid, H 2 SO±. — This acid has been known 
for centuries and was prepared by distilling ferrous 
sulphate, known as green vitriol. On account of this 
fact it was formerly called oil of vitriol. It is now 
manufactured by two processes, known as the chamber 
process, and the contact process. Each has its advan- 
tages although the second method is the cheaper. In 
both, sulphur dioxide is the starting point; as this gas 
is a waste product from most of our great western 
smelters it should be used for making sulphuric acid, 
but is mostly allowed to escape into the air. 

The Chamber Process. — In this country the sulphur 
dioxide needed is more often obtained by roasting iron 
pyrite, largely imported from Spain or elsewhere. This 
is passed into chambers where it meets nitric acid 
vapors and this reaction takes place: 

3S0 2 + 2HNO3 -» 3S0 3 + 2NO + H 2 

Steam is introduced and also currents of air: the steam 
reacts with the sulphur trioxide being formed, pro- 
ducing sulphuric acid. 



S0 3 + H 2 -> H 2 S0 4 

At the same time the oxygen of the air reacts with the 
nitrogen dioxide formed and it is again changed into 
nitrogen peroxide, thus: 

2NO + 2 -> 2N0 2 



188 CHEMISTRY FOR NURSES 

Immediately this peroxide reacts with more sulphur 
dioxide, thus: 

N0 2 + S0 2 -» NO + S0 3 

And then the preceding reaction is repeated indefi- 
nitely. It will be seen, therefore, that the nitrogen 
oxide is merely an agent, catalytic, for transferring 
the oxygen of the air to the sulphur dioxide. It is one of 
the few cases of catalytic action where we know exactly 
what the process is. It would appear that a very small 
amount of nitric acid to furnish the original nitrogen 
oxide would be sufficient for an indefinite time, but 
it must be remembered the air is four-fifths nitrogen 
and in removing this from the chambers, gradually the 
oxide escapes also: but the loss is very slow as means 
are taken to prevent it. The details probably are be- 
yond a book of this size. Fig. 33 will, however, give 
some idea of the process. The acid thus obtained is 
known as chamber acid and may safely remain in the 
chambers until it reaches a strength of 80 per cent 
when it begins to attack the lead-lined walls and floors. 
It must then be removed, after which it is concentrated 
by boiling in platinum or other vessels or used in the 
contact process as will be described later. 

The Contact Process. — By this method platinum is 
used as the catalytic agent. It might be supposed that 
a stream of air and heated sulphur dioxide passed 
through a tube would combine, but such is not the case. 
However, it is found that platinum will cause such a 
union, as we have seen it will do between hydrogen and 
oxygen even in the cold. Accordingly in order to 
spread a small amount of platinum which is very ex- 
pensive over a very great surface asbestos is dipped in 



SULPHUR AND COMPOUNDS 



189 



platinum chloride solution and heated. The chlorine is 
expelled and the platinum remains in a very finely 
divided form upon the asbestos. This is placed in a 
suitable tube, is heated and a stream of sulphur dioxide 
and air passed through it. Owing to the catalytic ac- 
tion of the platinum the oxygen and sulphur dioxide 
unite forming the trioxide, which though a solid is very 
volatile at the temperature of the tube. This is passed 
on into sulphuric acid of about such strength as that 
mentioned derived from the chamber process, when 




Ni-ter Pot ^ Pyrites Burners 



Fig. 33. — Chamber process for sulphuric acid. The escaping gases pass up 
the: Gay-Lassac tower where they meet the streams of sulphuric acid. This 
combines with the nitrogen oxide present, forming the niter acid, so called. 
This is pumped to the top of the Glover tower, where, descending, it meets 
the steam, which decomposes it. The nitrogen oxide then begins its work all 
over again. 



the two unite producing ultimately a white crystalline 
solid known as fuming sulphuric acid and the variety 
best suited for many purposes. Theoretically the tri- 
oxide might be passed directly into water, but when 
this is done great heat is produced such that consider- 
able portions of the trioxide are volatilized and lost. 
This does not happen when somewhat concentrated 
acid is used as described. 



190 CHEMISTRY FOR NURSES 

Characteristics of Sulphuric Acid. — Sulphuric acid 
is a colorless liquid, when pure, with a specific gravity 
of 1.84 and oily in appearance. It is exceedingly hy- 
groscopic and when water is added great heat is 
produced. In mixing the two water should never be 
poured into the acid, but the reverse and very slowly, 
in order that the water may take up the heat. In the 
proper amounts water may be brought almost to the 
boiling point and if the water is added to the acid rap- 
idly, the heat may produce sufficient steam to eject 
portions of the acid upon the person of the operator 
with serious results. On account of this property sul- 
phuric acid serves as an excellent drying agent for 
gases, accomplished by allowing them to pass slowly 
through it. On wood and sugar it serves to remove 
the hydrogen and oxygen present in the carbohydrates, 
leaving a charred mass ; certain invisible inks are 
simply very dilute sulphuric acid which upon heating 
loses its . water, becomes concentrated and chars the 
paper as just stated. As we have seen with metals in 
the electromotive series above hydrogen, it gives up 
its hydrogen, especially when diluted, for the metal; 
with metals less positive than hydrogen it only reacts in 
the concentrated condition and when heated, and then as 
an oxidizing agent, that is, it gives up a part of the 
oxygen, converting the metal into an oxide. Its boil- 
ing point is 330° C. but at this temperature it is largely 
decomposed forming trioxide and water. The fuming 
sulphuric is a crystalline solid, being really pure sul- 
phuric saturated with sulphur trioxide, with the for- 
mula, H 2 S 2 7 . It fumes from the fact that the trioxide 
is escaping and combining with the moisture of the air, 
condensing it into minute globules just as it has been 
said hydrogen chloride does. 



SULPHUR AND COMPOUNDS 191 

Uses of Sulphuric Acid. — It is said the civilization of 
a nation may be judged by the amount of sulphuric 
acid it uses. Certainly it is the most used of all the 
acids. It is necessary for the manufacture of prac- 
tically all other acids as well as many other chemicals. 
It is used extensively in making fertilizers from bones 
and native phosphate rocks ; for various explosives 
which we have already studied and for refining petro- 
leum in removing some of the tarry products which 
discolor the oils. 

Sodium Thiosulphate, Na 2 S 2 3 . — This is a compound 
of the theoretic thiosulphuric acid, H 2 S 2 3 . It is really 
sulphuric in which an atom of sulphur has taken the 
place of one of oxygen. The salt is sold frequently under 
the name of "hypo" or sodium hyposulphite, though 
wrongfully. It is used by photographers in fixing pho- 
tographic plates and prints and as an antichlor in re- 
moving the last traces from cloth of the chlorine used 
in bleaching them. 

Exercises for Review 

1. "What was the old idea of sulphur as related to the human 
body and to metals? 

2. "What is one of the oldest known deposits of sulphur? 
What is probably their origin? 

3. Where is the best deposit in this country? How is it ob- 
tained here? 

4. What other large deposit in the United States? 

5. How may sulphur be purified for medical purposes? 

6. Name the varieties of sulphur and describe each. 

7. How are rhombic crystals made? Monoclinic crystals? 

8. Which is the most stable form? How does it occur in 
nature? 

9. How is plastic sulphur made? How different from the yel- 
low variety? 

10. Give a medical use for sulphur; a horticultural use; two 
other uses. 



192 CHEMISTRY FOR NURSES 

11. What is vulcanite? Give several uses. 

12. What is a sulphide? How may metal sulphides be made? 

13. Name two sources of hydrogen sulphide in nature? 

14. Give chief properties of hydrogen sulphide. 

15. What are physiologic effects of hydrogen sulphide? Its 
antidote? 

16. Of what use is hydrogen sulphide to the chemist? 

17. Name the oxides of sulphur and give formulas. 

18. How. is sulphur dioxide made in the laboratory? How is 
the action different from that seen with other metals? How 
are the conditions different? 

19. Describe sulphur dioxide. 

20. Name one medical use of sulphur dioxide; three commer 
cial uses. 

21. Describe its use in drying fruit. How does it bleach? 
To what goods is it applied? Why do they return to their orig- 
inal color? 

22. Name four acids of sulphur and give formulas of each. 

23. What two processes of making sulphuric acid? What is 
the catalytic agent in each case? How does it act in the cham- 
ber process? 

24. What kind of acid is obtained by the contact process? 

25. Describe sulphuric acid. Why is invisible ink made of 
it not visible before heating? Why visible afterward? Will it 
become invisible again? 

26. Give several important uses of sulphuric acid. 

27. What is hypo? Give its uses. 



CHAPTER XVII 

THE NITROGEN FAMILY 

Outline — 

1. Names of Members of the Family. 

Why Classed Together. 

2. Phosphorus. 

(a) Discovery. 

(b) Occurrence in Nature. 

(c) Manufacture. 

(d) Forms of. 

(e) Comparison of Varieties. 

(f ) Uses of Each Variety. 

3. Matches. 

(a) Kinds. 

(b) Composition. 

4. Phosphate Foods. 

(a) Necessity. 

(b) How Manufactured. 

5. Fertilizers. 

6. Arsenic. 

(a) History of. 

(b) Occurrence. 

(c) Properties of. 

(d) Uses as a Metal. 

(e) Compounds. 

(f) Arsenic Poisoning. 

(g) Tests for Arsenic. 

(h) Treatment in Poison Cases. 

7. Antimony. 

(a) Description of. 

(b) Uses of Antimony. 

(c) Compounds of. 

8. Bismuth. 

(a) Properties of. 

(b) Uses. 

(c) Compounds of Bismuth. 

193 



194 CHEMISTRY FOR NURSES 

9. Comparison of Members of Family. 

Table of Compounds. 
Exercises for Review. 

1. Members of the Nitrogen Family. — Practically all 
of the eighty elements known arrange themselves into 
families as we have seen the four halogens clo. In the 
nitrogen family, besides this one already studied in 
connection w x ith the air, there are phosphorus, arsenic, 
antimony and bismuth. They are all solids except the 
first and taken as a whole are not strikingly alike in 
physical properties: but their chemical behavior and 
their compounds, as well as other considerations, make 
it certain that they should be classed together. 

2. Phosphorus. — Phosphorus was discovered in 1669 
by Brand. It received the name phosphorus, meaning 
light bearer, because it glows in the dark when exposed 
to the air. It is found in nature in the bones and teeth, 
in the form of calcium phosphate constituting about 
three-fifths their weight. In much smaller amounts it 
is found in the muscles in a complicated compound 
called lecithin and in the nerve centers. It is said that 
the sum total in the average human body would amount 
to somewhat more than three pounds, of which about 
90 per cent is in the bony structure; about 9 per cent 
in the muscles and 1 per cent in the brain and nerve 
centers. In some of the southern states, notably South 
Carolina, Florida and Tennessee, it is found in exten- 
sive deposits of calcium phosphate, Ca 3 (P0 4 ) 2 . 

Manufacture. — Phosphorus may be made either from 
bones or the native phosphate rock. At present it is 
mostly obtained from the native rock. This is mixed 
with silica, Si0 2 and charcoal or coke, and fed into an 
electric furnace. The heat causes the phosphorus to 
distill out as a vapor after which it is condensed under 



THE NITROGEN FAMILY 



195 



water, while the calcium silicate runs off as a slag from 
an opening at the bottom of the furnace. The essen- 
tial features are shown in Fig. 34. 

Forms of Phosphorus. — Like oxygen, carbon and sul- 
phur, phosphorus occurs in more than one form. Cor- 
responding to roll sulphur we have the waxy phos- 
phorus, sometimes called yellow or white phosphorus; 
besides this, corresponding to amorphous sulphur is 
the red phosphorus or amorphous. Each is convertible 
into the other under different circumstances. Under 
water in bright sunlight the yellow slowly changes into 




Fig. 34. — Manufacture of phosphorus. 



the red variety ; in a vessel containing no oxygen heated 
to about 250° C. the change is rapid. On the other 
hand if the red is heated to 300° C. and the vapors 
passed into water they condense again as the yellow 
variety. 

Comparison of the Two Varieties. — The waxy variety 
is of a very pale amber color when fresh but becomes 
yellower on exposure to light; the amorphous is of a 
dark reddish brown color. The yellow is soluble in 
carbon disulphide, the red is not. The yellow is very 



196 CHEMISTRY FOR NURSES 

poisonous, the other not. Taken internally one-sixth 
of a gram is a fatal dose oftentimes. Continual inhala- 
tion of the vapors produces a disease known as "phossy 
jaw" which is really a necrosis of the jaAY bones and 
is usually incurable. The yellow gives off a peculiar 
odor, the other none; yelloAV catches fire at 50° C, the 
other about 250; the one is luminous in the dark, the 
other not. 

Uses of Phosphorus. — Small amounts of phosphorus 
are employed in the manufacture of poisons for rats, 
mice, roaches and other vermin. The bulk of it, how- 
ever, is used in making matches. Of these there are 
two varieties. Originally matches were made by dip- 
ping the pine splints into molten sulphur and then tip- 
ping with a small amount of phosphorus mixed with 
some glue or other cementing material which protected 
it from the air. These are known as sulphur matches 
but are seldom seen at present except in certain por- 
tions of the country. They are very slow in getting 
started and moreover, give off sulphur dioxide, both of 
which reasons have led to their being discarded. Later 
paraffin was substituted for the sulphur as kindling for 
the splint, and to the head was added potassium chlo- 
rate or some other oxidizing material. These were 
rapid in their action and gave no offensive gas, but 
they were so easily ignited that many fires resulted. 
Moreover, children were often poisoned by them and 
the workmen in the factories were continually sub- 
jected to the fumes. Most countries passed laws 
against the manufacture of such matches and in the 
United States in 1913 they w x ere taxed out of existence, 
two cents being levied upon each hundred. At the 
present time therefore, the ordinary match has the 
paraffin for kindling, and in the head, a phosphorus 



THE NITROGEN FAMILY 197 

compound with some oxidizing material and giue or dex- 
trine to make it adhere. The friction produces suffi- 
cient heat to decompose the phosphorus compound and 
ignite the paraffin. 

3. Safety Matches. — In the safety match the phos- 
phorus of the red variety, mixed with some antimony 
trisulphide, is upon the box, while upon the match head 
is some oxidizing material like potassium chlorate, 
with, antimony trisulphide and glue or dextrine. It is 
only by great friction that the match may be ignited 
without rubbing on the prepared surface ; but when 
drawn over the box, a tiny amount of the red phos- 
phorus is converted into the yellow variety, catches 
fire and ignites the head of the match. 

Other Uses. — In the form of compounds phosphorus 
is essential both to plants and animals. Virgin soils 
as a rule are rich enough in phosphate for plant 
growth, but continued cropping, especially of grains, 
like wheat, removes it to such an extent that it must 
be restored by artificial means. Likewise the human 
body must have the phosphates for the proper nourish- 
ment of the bones, teeth and nerve centers. Of cereals 
wheat if used whole is the richest in phosphates; the 
legumes, beans and peas, are also rich in phosphates, 
likewise the yolk of eggs. 

4. Fertilizers. — The native phosphate rock as well as 
the bones are not soluble in water, hence not available 
as plant food. To render them suitable for fertilizer 
they are treated with sulphuric acid which changes 
them into what is known as the superphosphate, 
CaHP0 4 .H 3 P0 4 often written CaH 4 (POJ 2 . The by- 
product formed when this is done is a calcium com- 
pound of same composition as gypsum and this is left 
mixed with the superphosphate. Considerable amounts 



198 CHEMISTRY FOR NURSES 

of soluble phosphate are also obtained in preparing 
steel from phosphorus-bearing ores. 

6. Arsenic, As. — In order of density, the next ele- 
ment in the nitrogen family is arsenic with an atomic 
weight of 75. It has been known since the middle ages 
although at that time it probably had never been 
isolated. Its compounds were known and the fact had 
been observed that like mercury they had the power of 
turning a bright piece of copper silvery in appearance ; 
this was one of the reasons offered for the belief that 
copper could be changed into silver. 

Arsenic in Nature. — Arsenic occurs with many sul- 
phide ores of the metals and is often obtained as a by- 
product in their preparation. It is perhaps most often 
prepared from a sulphide and arsenide of iron, FeAsS. 

Description of Arsenic. — It is of a bright, steel gray 
color, but is usually tarnished so that it appears almost 
black. By heating in an open dish this dark coating 
soon disappears and the real color of the arsenic is 
seen. It vaporizes without melting and burns in the air 
when ignited, with a bluish white flame, producing the 
trioxide. It is crystalline in structure and very brittle. 

Uses of Arsenic. — In small amounts, about one-half 
of one per cent, it is mixed with lead in making shot. 
There are three reasons for this, the main one being 
that it gives greater fluidity to the melted mixture than 
lead alone has, so that when the alloy is poured from 
the top of a high tower, the shot become much more 
perfect than they would otherwise. A second reason 
which adds to the same end is that the melting point of 
the alloy is lower than that of lead and the mixture 
does not solidify so quickly, hence the drops have more 
time to become perfectly round. Third, the shot is 
somewhat harder for the small admixture of arsenic. 



THE NITROGEN FAMILY 199 

Arsenic Trioxide, As 2 3 . — This compound is sold at 
drug stores under several names, white arsenic, 
arsenous acid and even "arsenic." It is usually in the 
form of a white powder, is somewhat soluble in water, 
has a slightly sweetish taste, and is very poisonous. 
It is used somewhat in taxidermy to protect the skins 
against attacks of insects, as a common poison for ver- 
min, and to some small extent in medicine as a tonic, 
in the form of Fowler's solution. 

Antidote for Arsenic Poisoning. — Probably the best 
antidote is ferric hydroxide, freshly prepared. This 
is made by adding dilute ammonia water to a ferric- 
chloride solution and washing the precipitate to remove 
any excess of ammonia. Ferric hydroxide is a reddish 
brown, gelatinous precipitate as thus obtained and 
with the arsenic forms in the stomach an insoluble 
compound so that it is not absorbed by the system. 
This should be followed by an emetic or the use of the 
stomach pump. If for any reason ferric chloride can 
not be obtained magnesia stirred in water may be taken 
instead. It acts as does the ferric hydroxide though 
perhaps less rapidly. 

Tests for Arsenic. — There are several tests which may 
be made, some of them very simple. AYhat is known as 
Keinsch's is one of the easiest made. A few cubic cen- 
timeters of the arsenic solution are put into a test tube, 
some pieces of bright copper added and then some 
strong hydrochloric acid. The mixture is boiled for 
two or three minutes. The copper becomes silver col- 
ored if arsenic is present. Mercury compounds may 
give the same result, so in order to distinguish between 
them, the copper is taken from the tube, dried carefully, 
placed in a dry test tube and heated strongly. If the 



200 CHEMISTRY FOR NURSES 

deposit is arsenic, a white ring will appear on the 
cooler portion of the test tube, crystalline in character. 
Sometimes these crystals are very small so that they 
can not be detected by the naked eye, but they will 
sparkle as a rule held in sunlight. If the silver colora- 
tion is due to mercury, the ring forming upon the 
cooler portion of the tube will be made up of tiny drops 
of mercury and not crystalline. 

Marsh's Test. — This is by far the most delicate and is 
generally used in postmortem examinations. Various 
forms of apparatus are used but one of the simplest is 
shown in Fig. 35. The flask is prepared for the genera- 
tion of hydrogen from sulphuric acid by means of 
arsenic-free zinc. To be sure the zinc is pure it is tested 
thus: when the gas has been flowing long enough to 
remove all the air, and this is important, as the air mix- 
ture is very explosive, the jet is lighted. A cold dish 
is held against the flame. If the zinc is arsenic-free no 
spot appears upon the dish no matter how long held 
there. Next the arsenic solution is added through the 
thistle tube; the color of the flame, if arsenic is pres- 
ent in considerable amounts, changes from yellow to a 
pale lavender, and upon a cold porcelain dish held 
against the flame, a brownish-black spot with metallic 
luster is formed. Antimony compounds make a simi- 
lar spot, darker in color, more velvety in appearance, 
not soluble in a bleaching powder solution, while the 
arsenic spots are. This test it is said will detect the 
minutest portions of arsenic, even one part in several 
hundred thousand of water. The chemical reactions 
taking place are thus shown: 

Zn + H 2 S0 4 -» 2H + ZnS0 4 
H,As(X + 6H -> ILAs + 3H 2 



THE NITROGEN FAMILY 



201 



The hydrogen arsenide, formed in this second equation, 
also called arsine, is the most poisonous of the arsenic 
compounds: being a gas. care should be taken not to 
inhale it before lighting the jet, as small quantities are 
sometimes dangerous. 

2H 3 As - 30 2 -> 3H 2 + As 2 3 

This equation shows the reaction when the dish is not 
against the flame. The white fumes seen floating off 




Fig. 



-Marsh's test for arse 



into the air are arsenic trioxide. AVheii the dish is 
against the flame, they disappear as shown by the fol- 
lowing equation: 

4H 3 As + 30 2 -> As, + 6H 2 

The brown spots are the arsenic shown in the equation. 
Paris Green, Cu(C 2 H 3 2 ) 2 .CuHAs0 3 . — It will be seen 
from the formula that Paris green is a compound of 
copper and arsenic. It is bright green in color and was 
formerly used as a pigment, but on account of its very 
poisonous properties its place has been taken by coal 
tar products. Its chief use now is as an insecticide, 
especially for the Colorado potato beetle. 



202 CHEMISTRY FOR NURSES 

7. Antimony, Sb. — Antimony ranks next to arsenic 
in density, atomic weight, 120.2. It is a lustrous, steel 
white metal, does not tarnish in the air, highly crystal- 
line in structure and very brittle. Its physical proper- 
ties, therefore, are those of a metal; its chemical prop- 
erties are more nearly like those of the electronegative 
elements. 

Uses of Antimony. — When finely powdered it is black 
in color and is often used in rubbing upon plaster casts 
to give them the appearance of old bronze. Its most 
abundant use is for the manufacture of alloys such as 
type metal. This alloy contains tin, lead and antimony. 
The antimony gives hardness to the mixture and causes 
expansion upon solidifying. If type were made of lead 
alone, as it contracts when it solidifies, as most sub- 
stances do, the metal would withdraw from all the de- 
tails of the mold and the type would not produce legi- 
ble letters. Antimony causes a decided expansion so 
that when the type metal solidifies it fills every crevice 
no matter how small and gives clear, sharp type. It is 
also used in making Babbitt metal as well as many 
other alloys. 

Compounds of Antimony. — Antimony forms com- 
pounds like those of arsenic. Several of them were at 
one time used in Europe for medicine, but being very 
poisonous, many deaths resulted and laws were passed 
forbidding such use. Some are still used in veterinary 
medicine. The tartrate, KSbOC 4 H 4 6 , known as tartar 
emetic, is used to some extent as an emetic. The sul- 
phide, Sb 2 S 3 , is used in match heads as stated elsewhere 
in this chapter and to some extent in fireworks. 

8. Bismuth, Bi. — Its atomic weight is 208, hence by 
far the heaviest of the nitrogen family. Like arsenic 
and antimony it is crystalline in structure, and very 



THE NITROGEN FAMILY 203 

brittle ; it also expands on solidifying. Its color is 
darker than that of antimony with a golden or pur- 
plish luster, depending on how the light strikes it. 

Uses of Bismuth. — On account of its expansibility on 
solidifying it is used for the same purposes as antimony, 
but being much more expensive than antimony is em- 
ployed only for the more delicate castings and stereo- 
types. On account of its imparting low fusing point to 
alloys it is often used to make plugs and fasteners for 
protection against fire. In automatic sprinkling sys- 
tems in large department stores and elsewhere, the 
stoppers in various openings in the water pipes are held 
in position by plugs of a bismuth alloy. Even a small 
fire will melt these, the water pressure will then force 
out the stopper and automatically the water is turned 
on. In boilers a similar device is used to prevent ex- 
plosions. Fire doors, made of iron are often propped 
open by such fusible plugs: when melted away the door 
closes by means of a spring and the fire is confined to 
the single room. Metal booths for moving picture ma- 
chines have the openings provided in a similar way for 
automatically closing. A link in the chain which holds 
the shutter open is made of fusible metal; when this is 
melted the shutter closes by its own weight and the fire 
is kept within the booth. Wood's metal which is an 
alloy of bismuth has a melting point of only 60° C, 
which is lower than the temperature of a cup of hot 
coffee. 

Compounds of Bismuth. — Only one is of special im- 
portance and that because of its use in medicine. The 
subnitrate, formula, BiOX0 3 , also called the oxynitrate, 
is made from the ternitrate by treating with water and 
washing the precipitate. Thus: 



204 



CHEMISTRY FOR NURSES 



Bi(N0 3 ) 3 + H 2 0: 



: BiON0 3 + 2HN0 3 



It is a white powder, used as a cosmetic to prevent 
chapping of the skin, especially with small children, and 
as a remedy for certain stomach and intestinal troubles. 
9. Comparison of the Members of the Nitrogen Fam- 
ily. — The following table gives an idea of the various 
compounds of the members of this family and shows 
how closely they resemble in this respect. While they 
may differ materially in their outward aspect, or 
physical properties, their compounds are strikingly 
similar. 

Table For Comparison 





NITROGEN 
Nz=14 


PHOSPHOR- 
US 

P = 31 


ARSENIC 

As = 75 


ANTIMONY 

Sb = 120 


BISMUTH 

Biz=20S 


Hydrogen 
Compound 


Ammonia 
NH 3 


Phosphine 
PH 3 


A r sine 
AsH 3 


Stibine 
SbH 3 


None 


Oxides 


N,0 8 
N 2 Q 5 


p 2 o 3 
PA 


AS,Oo 

As 2 5 


SbA 
Sb 2 5 


BiA 
Bi 2 5 


Chlorides 


NC1 3 


PCI3 


AsCl 3 (?) 


SbCl 3 


BiCl 3 


Oxychlorides 


NOC1 


POCl 




SbOCl 


BiOCl 


Acids 


HNO3 


HPO3 

H 3 P0 4 


H 3 As0 4 


H 8 SbO, 


None 



Exercises for Review 

1. Give the names of the nitrogen family. Why are they 
classed together? 

2. When was phosphorus discovered and by whom? 

3. State where phosphorus is found in the human body and 
in what form? 

4. What amounts of phosphorus are found in the body? 

5. How is phosphorus manufactured and collected? 

6. Name the varieties of phosphorus and compare with cor- 
responding ones of sulphur. 

7. Compare red and yellow* phosphorus in six particulars. 

8. What is "phossy jaw"? What is the cause? 

9. Give two uses for phosphorus. Would the red variety do 
for the first? 



THE NITROGEN FAMILY 205 

10. How was the oldest match made? What objection to it? 

11. What objection to the "parlor match " of a few years 
ago? 

12. What is the composition of the ordinary match now? 

13. How is the safety match different from the ordinary? 

14. How is phosphorus supplied artificially to plants? What is 
the source of this fertilizer? How made? 

15. How is phosphorus supplied to the human body? Name 
some good foods for this purpose. 

16. How long has arsenic been known to scientists? Give 
some historical facts in connection with it. 

17. What are the most important properties of arsenic? 

18. Give one use for arsenic and three reasons for such use. 

19. What is arsenous acid? Give characteristics and uses. 

20. What are two antidotes for arsenic poisoning? How pre- 
pared for use? 

21. Describe Marsh's test for arsenic. What can be said of 
its delicacy? 

22. Describe Eeinsch 's test for arsenic. How distinguished from 
mercury? 

23. What is the composition of Paris green? What is its 
main use? 

24. Give chief properties of antimony. 

25. What are some of the uses of antimony? Give reason for 
such uses. 

26. Describe bismuth. 

27. What is the chief use of bismuth? What properties do its 
alloys have? 

28. Give some valuable uses of fusible alloys. What is melt- 
ing point of one? 

29. Name one valuable compound and give use of it in med- 
icine. 

30. Compare the members of this family as to hydrogen com- 
pounds formed; as to oxides; chlorides; acids. 



CHAPTER XVIII 

SILICON AND COMPOUNDS 

Outline — 

1. Natural Compounds of Silicon. 

(a) Silicon Dioxide, Silica. 

(b) Silicates. 

2. Water Glass. 

(a) How Made. 

(b) Uses. 

3. Window Glass. Crown Glass. 

■ (a) Preparation. 

(b) Properties. 

(c) Uses. 

4. Bohemian Glass. 

(a) Composition of. 

(b) Properties. 

(c) Uses. 

5. Flint Glass. 

(a) Composition. 

(b) Characteristics. 

(c) Uses. 

6. Manufacture of Glass Articles. 
Exercises for Review. 

1. Natural Compounds. — As shown by Pig. 9 on page 
57 silicon constitutes about one fourth of all the ma- 
terial of the earth. It does not occur free but certain 
compounds are very abundant and widely distributed. 
One of the most abundant is common sand, silicon di- 
oxide, formula Si0 2 . Many varieties of this compound 
are familiar. In transparent hexagonal prisms it is 
known as rock crystal; crystallized or not we have rose 

206 



SILICON AND COMPOUNDS 207 

quartz, smoky quartz, milky quartz, or amethyst, named 
from their color. Agate is mostly petrified wood in 
which silica has slowly replaced the cellular structure 
of the tree, preserving the rings of growth more or less 
perfectly and showing different colors as different for- 
eign matter has been introduced from time to time. A 
very large number of rocks are silicates, such as the 
felspars, kaolin, the clays, etc. 

2. Water Glass. — Silica is not soluble in water or any 
of the common acids ; but when fused with sodium car- 
bonate it reacts as shown by the equation: 

Si0 2 + Xa 2 C0 3 -> Na 2 Si0 3 - C0 2 

Sodium silicate thus prepared is a nearly colorless, flint- 
like looking compound, with few uses. If instead of 
boiling dry to obtain the solid, it is left in the form of 
a solution, as is usually done, it has about the con- 
sistency of glycerine, and if pure not specially different 
in appearance. It is thus sold under the name of water 
glass and has manifold uses. For the manufacture of 
paper boxes and in many similar places where glue was 
formerly used, water glass is now being substituted, 
being cheaper. It is also used as a cementing material 
in many ways; and mixed with nine parts of water it is 
recommended as a preservative for eggs. The solution is 
poured into a jar and the eggs added as obtained. They 
I should be covered by the solution and the jar kept 
1 covered to avoid excessive evaporation. It is probably 
I the best method known of preserving eggs, as they will 
' keep reasonably well for nine to twelve months. The 
I solution fills the pores of the shell and prevents germs 
I causing decomposition from entering. 

3. Window Glass. — This is a cheap variety of glass 



208 



CHEMISTRY FOR NURSES 



formed by fusing together lime, sodium carbonate and 
silica. The resulting product is a sodium calcium 
silicate, not soluble in water as is the sodium silicate 
just studied. It is usually greenish in color due to the 
presence of small quantities, of iron compounds. This 
may be removed largely by adding a small amount of 
manganese dioxide at the time of fusing the mixture. 
Any excess of the manganese will give the glass a violet 
tinge a small amount of which is not objectionable. 
This variety of glass has a comparatively low melting 
point and may be readily softened in the Bunsen burner. 
It is used for making test tubes and most of the glass 
tubing for the laboratory because of the fact that it may 
be bent into all sorts of shapes as occasion may demand. 
It is often called crown glass. 

4. Bohemian Glass. — If potassium carbonate is sub- 
stituted for the sodium carbonate in crown glass we 
have produced what is known as Bohemian glass. It is 
more transparent than crown, less easily attacked by 
laboratory reagents, and of much higher melting point. 
It is used therefore for combustion tubes, which are 
often subjected to high temperatures, beakers, flasks 
and various other scientific glassware, also for fine 
glassware in the home. 

5. Flint Glass. — A third variety of glass is made by 
fusing together silica, potassium carbonate and lead 
oxide instead of lime. A beautiful clear glass is ob- 
tained called flint f or in its purest variety paste, glass. 
It is much heavier than either of the other varieties, 
is very highly refractive, softer and much easier cut. 
Prom it are made the various articles of cut glass found 
on the sideboard, and lenses for all purposes, magnify- 
ing glasses, telescopes, eyeglasses, etc. Paste is used 
for making imitation diamonds. Their brilliancy at 



SILICON AXD COMPOUNDS 209 

first, while not equal to the diamond, is good, but being 
so very soft they soon become scratched and lose their 
value. 

6. Making of Glass Articles. — Tumblers and similar 
glass articles are as a rule molded. Bottles are blown 
by inserting a long hollow tube with a suitable amount 
of molten glass upon the end into a mold and blowing 
till the mold is filled. The open end is then finished 
in a rimming machine. Large plate glass windows are 
made by pouring the glass upon a table and rolling with 
heavy iron rollers while the glass is still hot. Later it 
is ground till perfectly smooth, and polished. 

Exercises for Review 

1. What is the most abundant natural compound of silicon? 

2. Name several varieties of silica. Give colors of them. 

3. What are kaolin; felspar; clay? 

4. How is water glass made? What is its appearance? Its 
uses? 

5. Why do eggs preserved in water glass crack when boiled? 

6. From what is window glass made? What uses are made 
of crown glass in the laboratory? Why? 

7. From what is Bohemian glass made ? Give its characteris- 
tics ? 

8. What are its chief uses? Why in the laboratory? Why in 
the home ? 

9. From what is flint glass made? What are its chief proper- 
ties? 

10. Would Bohemian glass do as well to make imitation dia- 
monds ? Why ? 

11. What use has flint glass in the home? Why so used? 

12. How are tumblers made? Bottles? Plate glass? 



CHAPTER XIX 
SODIUM FAMILY AND ITS COMPOUNDS 

Outline — 

1. Names of the Members. 

2. Natural Compounds of Sodium. 

3. Acid Sodium Carbonate. 

(a) How Prepared. 

(b) Uses. 

(c) Baking Powders — 

Composition. 

Kinds. 

Chemical Action. 

Comparative Healthfulness. 

4. Yeast Bread. 

5. Aerated Bread. 

6. Sodium Carbonate. 

(a) Preparation. 

(b) Uses. ' 

7. Sodium Hydroxide. 

(a) Preparation. 

(b) Uses. 

(c) Soaps. 

8. Borax. 

9. Potassium Nitrate, Uses. 

10. Potassium Carbonate. 

(a) Sources in Nature. 

(b) Uses. 

(c) Suint and Lanolin. 

11. Other Potassium Compounds. 

(a) Potassium Chlorate. 

(b) Potassium Hydroxide. 

(c) Potassium Bromide. 

(d) Potassium Iodide. 
Exercises for Review. 

210 



SODIUM FAMILY AND ITS COMPOUNDS 211 

1. Members of the Family. — There are only two im- 
portant members of the family, sodium and potassium. 
There are three others, lithium, rubidium and caesium. 
They are known as the alkali metals, for when added 
to water, as we have seen in the case of sodium and 
potassium, they form alkalies. In the chapter on salt 
we have already studied sodium. Its compounds are 
of the greatest importance and will be taken up at this 
time. 

2. Natural Compounds of Sodium. — Common salt 
has alread}" been mentioned and its abundance. The 
only other needing mention is Chile saltpeter, sodium 
nitrate, used as stated elsewhere for fertilizer and for 
making gunpowder. 

3. Acid Sodium Carbonate, NaHC0 3 . — This is also 
known as sodium bicarbonate and as cooking soda. It 
is made from common salt by what is known as the 
Solvay process which consists of passing a current of 
ammonia and one of carbon dioxide into a saturated 
solution of salt. Not being very soluble in water, the 
acid carbonate separates out in fine crystals. The re- 
actions are given below: 

NH 3 + H 2 -> NH 4 H0 
NH 4 H0 + C0 2 -* NH 4 HC0 3 
NH 4 HC0 3 + NaCl -» NaHC0 3 + NH 4 C1 

The process is very cheap for the ammonium chloride 
obtained in the third step may be treated with lime and 
the ammonia recovered for carrying on the process. 

Some Uses for Soda. — The more common uses for 
soda are in the household in cooking. When soda is 
used for leavening bread, it is brought into contact with 
sour milk, which contains lactic acid. The soda and 



212 CHEMISTRY FOR NURSES 

acid react setting free carbon dioxide and this held in 
by the gluten in the flour, expands because of the heat 
and causes the "biscuit" to rise. The action between 
the acid and soda is shown by the equation, 

NaHC0 3 + HC 3 H 5 3 -> C0 2 + H 2 + NaC 3 H 5 3 . 

From this reaction there is left in the bread sodium lac- 
tate, NaC 3 H 5 3 , which so far as known is harmless. 
The amount of acid in sour milk varies greatly, how- 
ever, hence it is difficult to so apportion the soda as to 
effect exact neutralization. An excess of soda becomes 
known by brown spots in the bread or by the whole 
mass being more or less yellow and by the unpleasant 
alkaline taste. It was this difficulty which led to the 
adoption so largely of baking powders for soda. 

Baking Powders. — All baking powders contain soda. 
The other active ingredient is some chemical which 
takes the place of the acid in the sour milk. Often this 
is an acid salt; sometimes a neutral salt which has the 
power of decomposing the soda. In all cases carbon 
dioxide is set free as already described and lightens 
the bread in the same way. A third substance is neces- 
sary as a preservative; this is starch or flour and sim- 
ply serves to prevent any chemical action taking place 
before moisture is added in the dough. The starch cov- 
ers the particles, as has been described elsewhere in 
keeping salt dry, so that they do not take up moisture 
from the air and do not come in contact with each 
other. 

Kinds of Baking Powders. — There are numerous 
brands of baking powders, but probably all may be put 
under four classes; phosphate powders, cream of tar- 
tar powders, alum, and mixed. The phosphate powders 



SODIUM FAMILY AND ITS COMPOUNDS 213 

contain soda, acid calcium phosphate, starch. The tar- 
trate powders have soda, cream of tartar and starch; the 
alum powders, soda, aluminum sulphate and starch; the 
mixed, some variation of the above. What happens in 
the dough is shown by the following equations: 

2 NaHC0 3 + CaH 4 (P0 4 ) 2 -» 

2 C0 2 + 2H 2 + CaHPO, + Xa.HPO, 
NaHCO s + KHC 4 H 4 6 -» C0 2 + H 2 + KNaC 4 H 4 e 

6 NaHC0 3 + Al 2 (SOJ 3 -> 3C0 2 + A1 2 (C0 3 ) 3 + 3Na 2 S0 4 

In the last case a second reaction takes place between 
the aluminum carbonate produced and the water pres- 
ent, as follows: 

A1 2 (C0 3 ) 3 + 3H 2 -> 3C0 2 + Al 2 (HO) 6 

Comparative Health fulness. — There has been a great 
controversy for years as to which is the more healthful 
powder and each manufacturer has made claims for 
his own against the others. The question depends upon 
the residue left in the bread. By examining the equa- 
tions given above it will be seen that the first mentioned 
leaves two acid phosphates: the second a tartrate, 
known in medicine as Rochelle Salts; the third leaves 
two, sodium sulphate and aluminum hydroxide. Which 
is the least harmful of all these? Mr. Leach, who is 
perhaps the best authority on the subject in the United 
States, says that all these residues are recognized in 
the pharmacopeia as drugs, which in large amounts 
are harmful in their effects upon the system. But in 
small amounts, as found in our bread, no experiments 
have ever been made, as were with the famous 
"poison squad" in Washington City a few years ago 
by Dr. Wiley upon various food preservatives. In the 



214 CHEMISTRY FOR NURSES 

absence of such data he does not presume to answer 
the question. If such authorities can not, it ill behooves 
people with less experience to do so. The ideal leaven- 
ing agent, were there not such great difficulties in the 
way, would be soda and hydrochloric acid. As the 
equation shows, there would be left as a residue only 
common salt 

NaHC0 3 + HC1 -> C0 2 + H 2 + NaCl. 

The amount of salt thus produced is not as great as 
that usually added to the bread, hence could not be open 
to objection. 

4. Yeast Bread. — In yeast bread no chemical agent 
is used as a leaven. A microscopic plant called yeast 
is introduced into the dough and it produces the carbon 
dioxide through its action on the sugar and starch 
present. This has already been seen in another chapter. 
The equation is 

C 6 H 12 6 -» 2C0 2 + 2C 2 H 5 OH. 

The carbon dioxide plays the same part as in all other 
cases, and on baking, the alcohol escapes on account of 
its low boiling point. There are objections to this 
method of making bread and difficulties to be overcome. 
There is a considerable loss of weight owing to the 
conversion of the flour into carbon dioxide and alco- 
hol, both of which are volatile. In baking, this loss, 
including the water also given off, amounts to as much 
as 15 to 20 per cent. Liebig, the German chemist, 
some years ago estimated that in the German empire 
12,000,000 gallons of alcohol were produced every year 
in the process of bread making all of which was lost, 



SODIUM FAMILY AND ITS COMPOUNDS 215 

It will be seen, therefore, that this is a very wasteful 
method. Various attempts have been made to save this 
alcohol, but none of them successful. Further, if the 
process be continued too long, acid fermentation takes 
place, and the bread will be sour. 

5. Aerated Bread. — On account of the loss in making 
yeast bread efforts have been made to force air into 
the dough as it is being kneaded. Such bread has a 
sweet, wholesome taste, but seems inclined to be dry and 
"chaffy" more like stale yeast bread and has not been 
received with favor by the public. Its wholesomeness 
is above question. 

6. Sodium Carbonate, Na 2 C0 3 . — Most of the sodium 
carbonate on the market now is made from the acid car- 
bonate by heating, whereby the hydrogen passes off in 
the form of water, thus: 

2NaHC0 3 -> H 2 + C0 2 + Na 2 C0 3 . 

The carbon dioxide expelled is used again in the Solvay 
process as already described. This gives an anhydrous 
carbonate, a fine white powder. If the crystalline va- 
riety, sal soda, is desired, the anhydrous is dissolved 
in water and allowed to crystallize, when ten molecules 
of water are taken up, forming Na 2 CO 3 .10 H 2 0. This 
form is used in scrubbing and for like purposes prob- 
ably because much more readily soluble in water. 

Washing Powders. — Nearly all such powders contain 
sodium carbonate as the principal ingredient : in addi- 
tion some of them contain fine pumice stone, small 
amounts of sodium hydroxide, powdered soap, etc. 
Pumice is an abrasive and if used on silver or fine 
articles is apt to scratch them, 



216 CHEMISTRY FOR NURSES 

Other Uses of Sodium Carbonate. — Sodium carbonate 
has numerous other uses, one of the more important of 
which is for the manufacture of common window and 
other cheap grades of glass; it is used in the manufac- 
ture of caustic soda, sodium hydroxide, a very valuable 
compound, and for softening water. This last is a very 
important and extensive use. It will be studied later. 

7. Sodium Hydroxide, NaHO. — Sodium hydroxide is 
made from sodium carbonate by treating with slaked 
lime, calcium hydroxide. The equation shows the 
reaction, 

Na 2 C0 3 + Ca(HO) 2 -> CaC0 3 + 2NaHO. 

The calcium carbonate is not soluble in water hence 
precipitates out and the sodium hydroxide solution is 
boiled to dryness. The commercial article always con- 
tains a considerable percentage of sodium carbonate. 
It is purified by dissolving in alcohol and evaporating 
again. 

Uses of Sodium Hydroxide. — The chief use is in the 
manufacture of soap. This is made as described else- 
where by boiling with some fat or oil. For the cheaper 
grades of laundry soap rosin is used to take the place 
of a considerable portion of the grease. It makes a 
yellow soap of a quality inferior to an all-fat soap. 

Kinds of Soap. — A very great variety of soap is 
on the market. Those more or less translucent are 
what are known as glycerine soaps. From them the 
glycerine has not been removed; the crude soap has 
been dissolved in alcohol which separates the opaque 
portions, the alcohol is evaporated and the soap molded 
into cakes. Such soaps are expensive because of the 
added labor in making and for the consumer costly also 



SODIUM FAMILY AND ITS COMPOUNDS 217 

because being much more soluble in water they do not- 
last long. Floating soaps are made so at least partly 
by having tiny bubbles of air blown into the pasty mass 
before cold. They are usually more free from water, 
hard compressed, and last longer for these reasons. 

8. Borax, Na 2 B 4 O 7 10H 2 O. — This compound is largely 
derived from California deposits of calcium borate 
which is treated with sodium carbonate. Thus: 

CaB 4 7 + Na 2 C0 3 ■-> CaC0 3 + Na 2 B 4 7 . 

The calcium carbonate is filtered out and the borax 
boiled to point of crystallization. AVhen the borax sepa- 
rates out it takes up ten molecules water of combina- 
tion as shown in the formula. Borax is a constituent of 
many washing powders, and in the household is often 
used to soften water, but is much more expensive for 
this purpose than sal soda. Mixed with glass it is used 
in glazing porcelain ware and in enameling: also as a 
flux in soldering and in small amounts as a preservative 
in food products. 

9. Potassium Nitrate, KN0 3 . — To a much smaller ex- 
tent than the corresponding compound of sodium, po- 
tassium nitrate is found free in nature. It is a white 
crystalline salt, used as a preservative for meats, and 
in making gunpowder. The usual composition of this 
explosive is 

Saltpeter, KN0 8 , 75 per cent 
Sulphur, 12 " " 

Charcoal, 13 " " 

In firing it, a detonator, like mercuric cyanate (ful- 
minate) in a percussion cap is used; this starts the de- 
composition of the nitrate which furnishes free oxygen 
to burn the carbon and sulphur. Some of the products 



CHEMISTRY FOR NURSES 

formed are solids hence the smoke always noticed in 
exploding this kind of powder. 

10. Potassium Carbonate, K 2 C0 3 . — Potassium carbon- 
ate, often called pearl ash, is found in wood ashes, in 
sugar beets, and in the oily deposit called suint found 
on the wool of sheep. The first source is no longer 
a valuable one, although at one time it furnished a con- 
siderable amount of that used in commerce. The sugar 
beet industry is increasing from year to year and with 
it the supply of potassium carbonate. In preparing wool 
for manufacture, it is treated with hot water which 
removes the grease and potash salt. The oily matter 
is refined and put on the market for the drug trade 
under the name of lanolin and is used in making various 
salves and ointments. Potassium carbonate is used 
mainly for the manufacture of other potassium com- 
pounds and for Bohemian glass which is mentioned 
elsewhere. 

11. Some Other Compounds. — Potassium chlorate is a 
white crystalline solid often sold in the form of tablets 
as a throat medicine. It has a cooling, mild taste, which 
tends to allay any slight irritation of the throat. Po- 
tassium hydroxide, KHO, is used for making soft soap. 
By saponifying it with linseed oil a special variety of 
soft soap is made for the drug trade for making salves 
and various other pharmaceutic preparations. Potas- 
sium bromide, KI, is used in tablet form as a sedative 
in nervous headache, sleeplessness and like troubles. 
Potassium iodide is also used medicinally. 

Exercises for Review 



1. Name the members of the sodium family, Which are the 
important ones? 

2. Why are they called alkali metals? 



SODIUM FAMILY AND ITS COMPOUNDS 219 

3. Name the two natural compounds of sodium and state 
where found. 

4. What is cooking soda? How made from salt? 

5. Explain the action of soda in making biscuits. 

6. What do baking powders contain in common? Purpose of 
it? 

7. Name the kinds of baking powders. Give composition of 
each. 

8. What must be known to decide as to the healthfulness of 
any baking powder? 

9. Give the chemical action in a baking powder and compare 
with soda. 

10. Explain the action of yeast. What causes the bread to 
rise ? 

11. Why is yeast bread not made from corn meal or flour? 

12. Why is il raising" bread a wasteful pro-cess? 

13. What is aerated bread? What can you say of its whole- 
someness? 

14. How is anhydrous sodium carbonate made? Soda crystals? 

15. Give the chief uses of sodium carbonate. 

16. What is the chief use of caustic soda? What by-product 
is furnished? 

17. What is a glycerine soap? Why expensive? 

18. Where does our borax supply come from? What are some 
of the uses? 

19. Give composition of gunpowder. How is it exploded? 
Give purpose of each ingredient. Why not smokeless? 

20. Give three sources of potassium carbonate. Which is the 
most important? 

21. What is suint? What is lanolin? 

22. What is the most important use of potassium carbonate? 

23. Name four other potassium compounds with some use of 
each. 



CHAPTER XX 

THE CALCIUM FAMILY 

Outline — 

1. Members of the Family. Another Name for Group. 

2. Calcium. 

(a) Discoverer of. 

(b) Method of Preparing. 

3. Natural Compounds of Calcium. 

(a) The Carbonate — Interesting Forms. 

(b) The Sulphate. 

4. Artificial Compounds. 

(a) Lime — Preparation. 

'Uses. 

(b) Precipitated Chalk. 

(c) Plaster Paris — Preparation. 

Uses. 

(d) Calcium Chloride. 

(e) Cements — Kinds. 

Characteristics. 
Uses. 

5. Hard Waters. 

(a) Kinds of. 

(b) Troubles and Expense of. 

(c) How Softened — On Large Scale. 

In Household. 

6. Strontium and Barium Compounds. 

Use of. 

Composition of Colored Fires. 
Exercises for Keview. 

1. Members of the Family. — Belonging to this family 
there are besides calcium, the most important, barium, 
strontium and, radium. After the sodium group they 

220 



THE CALCIUM FAMILY 221 

are the most strongly positive of the metals. Their ox- 
ides as a rule are somewhat soluble in water and pro- 
duce strong alkalies, from which they are called the 
"alkaline earth" group. 

2. Calcium, Ca, Atomic Weight, 40. — Calcium was dis- 
covered by Sir Humphrey Davy early in the nineteenth 
century through electrolysis of the chloride. It is now 
prepared in the same way and may be had from the 
larger supply houses. It reacts with cold water though 
much less violently than does sodium and can be used 
in the preparation of hydrogen from water. 

3. Natural Compounds of Calcium. — There are two 
natural compounds found in abundance, the carbonate 
and sulphate. The first of these was mentioned when 
we were studying carbon dioxide. Chalk and all sim- 
ilar natural carbonates of calcium have been produced 
from the shells of sea animals which had the power of 
absorbing the small amounts of calcium carbonate from 
the water and storing it up as a protective covering for 
themselves. Chalk beds result from a microscopic an- 
imal of this kind; limestones from larger ones such as 
crinoids, and mollusks of all kinds. The well-known 
Coquina rock, used in making the old fort at St. Augus- 
tine, Florida, is composed of pieces of shells, cemented 
together, so large that even a superficial examination 
shows the character. Calcium sulphate in nature is 
known as gypsum: it occurs sometimes beautifully 
crystallized and in one delicately tinted variety is 
known as alabastine, used in making vases and other 
articles of like character. 

4. Artificial Compounds — Lime, CaO. — Lime is made 
in kilns by heating at a high temperature limestone 
rock for several days. During the process carbon diox- 
ide is expelled as shown by the equation, 



222 CHEMISTRY FOR NURSES 

CaC0 3 (heated) -» CaO + C0 2 

It is a white, amorphous solid, with strong attraction 
for moisture and also, if moist, for carbon dioxide. 
Exposed to the air it rapidly crumbles to a powder and 
forms what is called air-slaked lime, with the composi- 
tion of Ca(HO) 2 . Further exposure results in the ab- 
sorption of carbon dioxide and a reversal of the orig- 
inal process forming again calcium carbonate. These 
two facts are shown in the two equations, 

CaO + H 2 (from the air) ->Ca(HO) 2 

Ca(HO) 2 + C0 2 ->CaC0 3 . 

If water is added to a lump of lime, chemical union be- 
gins, the lump swells, much heat is generated and the 
lime becomes water slaked. Owing to this being an 
easy way of obtaining a considerable amount of heat 
without danger of fire balloonists on long trips usually 
carry some lime and water. Large amounts of lime, 
however, exposed to water generate sufficient heat to 
set fire to any combustible materials present. In the 
flood at Kansas City in 1903 many box cars loaded with 
lime standing in the yards were about half submerged: 
all of them caught fire and burned to the water's edge. 
Uses of Lime. — In small quantities it is molded into 
sticks and used in the calcium light mentioned else- 
where. Slaked, it is used in removing the hair from 
hides, preparatory to tanning; boiled with sulphur, as 
a spray for fungi on fruit. This has been studied under 
sulphur. One of the most important uses is in making 
mortar for masonry work of dwellings. For large 
buildings it does not possess the tensile strength neces- 
sary. In making mortar it is first slaked with water, 



THE CALCIUM FAMILY 223 

and sand is added. For the better grade of houses 
this is "tempered" by the addition of a small amount 
of cement. When put into the foundation, hardening 
takes place first through the loss of water and following 
this by the absorption of carbon dioxide from the air. 
This has been shown by an equation in section 4 above. 
This last process, therefore, may go on for years. An- 
other very important use is for softening water as will 
be explained elsewhere ; also with alum to precipitate 
the mud in city water supplies. In the form of lime 
water, which is a solution of the hydroxide in water, 
it is used often as a dilute alkali in medicine ; and also 
as milk of lime, which is limewater with considerable 
portions of the hydroxide in suspension. 

Precipitated Chalk. — This is calcium carbonate made 
by adding sodium carbonate to a solution of calcium 
chloride: the precipitate is washed thoroughly and 
dried. Properly made it is a fine, white powder, devoid 
of any gritty feeling and often used as an ingredient 
of tooth powders and tooth pastes. 

Plaster of Paris, CaSO+.H 2 0. — This well-known com- 
pound is prepared from gypsum, as lime is from lime- 
stone. As the native rock is heated, a portion of the 
water of combination, about one-fourth, is expelled 
leaving a compound with the formula given above. It 
is a fine white powder, whose most striking property 
is that of hardening rapidly when mixed with water. 
This is called "setting;" when it takes place, the plaster 
of Paris again takes up the water previously expelled 
on heating and returns to the former hydrated condi- 
tion. 

Uses of Plaster of Paris. — For very white walls it is 
mixed with lime "putty," slaked lime in the form of a 



224 CHEMISTRY FOR NURSES 

thick paste, and applied as the finishing coat in plas- 
tering. For ornamental, raised frescoes, panels, and 
similar ornamental work about large buildings plaster 
of Paris is extensively used. It also serves as a filler 
for much of the paper used and is the principal ingre- 
dient of many of the crayons used in the school room, 
also is very commonly applied in dentistry and surgery 
for casts. 

Calcium Chloride, CaCl 2 . — Calcium chloride is ob- 
tained as a by-product in several manufacturing proc- 
esses. It has some uses in the chemical laboratory for 
drying gases, and on account of its being deliquescent 
has been tried in government experiments in maintain- 
ing roadways. In many places roads are maintained 
by the application of an asphalt oil ; this prevents dust, 
wear by heavy traffic, and erosion by heavy rains. Cal- 
cium chloride serves mainly to prevent the formation 
of dust and hence the loss of material by winds and 
rapid traffic. It does this by absorbing moisture from 
the air and thus keeping the roadway slightly damp all 
the time. In rainy seasons or in climates where there 
is apt to be heavy rain at any time it is not satisfactory 
because it is rapidly dissolved and carried away in the 
water. Another use for it is a brine in refrigeration. 
Claims are made for it that it attacks the metal pipes 
and containers less than a solution of common salt more 
often used. As it can be reduced much lower in tem- 
perature than ordinary salt brine without freezing, it 
is especially adapted to refrigeration where the brine 
must be transmitted some distances from the ammonia 
plant. This is often done in large cities. 

Cements. — Recent United States bulletins show an 
output of cement for the year of 1915 at close to 90,- 
000,000 barrels and the output increasing rapidly for 



THE CALCIUM FAMILY 225 

the last ten years. This will probably continue under 
normal conditions for years to come. There are two 
kinds of cements, natural and portland. When a rock 
quarry contains in its various layers all the different 
kinds of rock necessary for the preparation of a cement 
the product obtained is called a natural cement. Usu- 
ally, however, some portions must be obtained from 
one quarry and other portions from another. In such 
cases the cement is spoken of as artificial or portland. 
As the latter kind may have the necessary ingredients 
carefully weighed out in such proportions as experience 
has shown to give the best results, they are usually 
stronger and are preferred for large structures or for 
those which must stand great strain, such as sky-scrapers 
and concrete bridges. Usually the composition of 
natural cements is such that they harden more slowly 
hence are not suited for such places as sewers, bridge 
piers or wherever there is apt to be much water. Con- 
crete is a mixture of cement, sand, and crushed rock in 
the proportions for ordinary work of one, three and five. 
These amounts are varied, however, according to the 
kind of work. Cements harden in two ways. One or two 
of the constituents being made from carbonate rock take 
up carbon dioxide from the air as lime does and change 
back to the original rock. This part of the process is 
slow, as already described: the remainder of the cement 
originally was a hydrated silicate which lost a portion 
of its water when the rock was heated in making the 
cement. This portion, like plaster of Paris, hardens by 
taking up again the water of combination. Reinforced 
concrete is concrete containing iron rods or wire or iron 
in some form to give added strength in case of sudden 
shocks or strain. 



226 CHEMISTRY FOR NURSES 

5. Hard Waters. — Any water containing minerals in 
solution which will form a precipitate when soap is added 
is called hard. There are two kinds of hardness, tem- 
porary and permanent. Temporary hardness consists 
usually of the acid carbonate of calcium or iron, while 
permanent hardness is more often the sulphate of cal- 
cium or magnesium. Temporary hardness is called such 
because it may be removed by boiling the water, while 
permanent hardness can not be removed thus. Acid 
salts are usually less stable than normal salts: in this 
case when the water is boiled the acid carbonate is thus 
decomposed, 

CaH 2 (C0 3 ) 2 -> CaC0 3 + H 2 + C0 2 

The calcium carbonate is not soluble in water hence it 
precipitates out. It is this fact which causes much of 
the trouble arising from temporary hardness. It forms 
on the inside of the pipes in steam boilers, the hot water 
coils in our furnaces and elsewhere. A layer of this 
called "boiler scale" or simply "scale" a quarter inch 
in thickness causes a loss of half the heating effects. 
As this accumulates it becomes very difficult to heat 
the water at all: more than this the iron pipe itself be- 
comes very hot, as the heat is not transmitted to the 
water, it is rapidly burned away and the pipe bursts. 
It is one of the great problems for all railroads running 
through country where the water is hard. Pig. 36 
shows sections of two pipes — an actual case — thus 
nearly filled with scale. Moreover, hardness is a great 
annoyance and expense in other ways. As long as any 
exists in the water, soap can not do anything toward 
cleansing. As stated above when soap solution comes 
in contact with such salts as produce hardness it forms 
a curdy precipitate which rises to the top of the water 



THE CALCIUM FAMILY 227 

and until all the hardness is removed the soap con- 
tinues uniting with it rather than forming an emulsion 
to remove the grease which holds the "dirt." In cities 
using a hard water for their daily supply the expense 
is very great. In Glasgow, Scotland, some years ago 
the soft waters from a lake were substituted for their 
former supply and in the first year the saving in soap 
was estimated at $200,000. This is such an item that 
even a low degree of hardness makes it necessary for 
steam laundries to use every effort to remove it. Many 
of them use from 50,000 to 100,000 gallons of water a 




Fig. 36. — Scale in iron pipes. 

day. This is received from the city mains into large 
tanks where it is treated with milk of lime and sodium 
carbonate solution. Analyses are made of the un- 
treated water daily and these chemicals added in just 
such proportions as are needed so that there shall be no 
excess. What happens is shown by the equations: 

CaH 2 (C0 3 ) 2 + Ca(HO) 2 -* 2CaCO a + 2H 2 

In this, the hardness being an acid salt will combine 
with an alkali, and is thus converted into an insoluble 
compound and settles out of the water. 



228 CHEMISTRY FOR NURSES 

CaS0 4 + Na 2 C0 3 -* Na 2 S0 4 + CaC0 3 

In this case, the permanent hardness is removed by the 
calcium salt being converted also into an insoluble 
compound, the same as in the preceding and settles out 
with the other. In the home, water if very hard should be 
treated with a small amount of sodium carbonate before 
using for laundry purposes, or the bath room. A small 
amount of ammonia w r ater will do no harm, but is more 
expensive than the sal soda. Such treatment will be 
found to effect a great saving of soap at much less cost. 

6. Strontium and Barium Compounds. — These are 
not of great importance to us. There are two, however, 
that are of interest, the nitrates: they are used in mak- 
ing fireworks and colored fires. Strontium imparts a 
beautiful red and barium a green, and the nitrates, be- 
ing unstable, are commonly used. For tableaux where 
electric spot-lights are not available the colored lights 
are obtained in this way, by making a mixture of pow- 
dered shellac, potassium chlorate and strontium nitrate 
for the red. If green is desired, barium nitrate is sub- 
stituted for the strontium. 

Exercises for Review 

1. Name the four members of the calcium family. 

2. By what other name are they known? 

3. Who discovered calcium? How? How made now? 

4. Name the natural compounds of calcium and give some 
special forms. 

5. How is lime made? Give its most important properties. 
G. Give several important uses of lime. 

7. What is precipitated chalk? What are some of its uses? 

8. How is plaster of Paris made? Its chief property? 

9. What chemical change takes place when plaster of Paris 
sets? 



THE CALCIUM FAMILY 229 

10. Give some important uses of it : some uses in surgery. 

11. What is the chief property of calcium chloride? Give 
three uses. 

12. What two kinds of cements are there? Explain the differ- 
ence. 

13. What two processes are involved in the setting of ce- 
ments? Compare with lime and plaster of Paris. 

14. What is hard water? Two kinds? How can you know 
whether a water is hard ? 

15. What trouble does hardness cause the engineer? 

16. What trouble in our homes from hardness ? What expense ? 

17. Show how laundries soften their water. Explain what 
happens. 

IS. What is the best way to soften bath or laundry water at 
home? Why not use lime water? 

19. Xame one barium and one strontium compound of inter- 
est. Why ? 

20. Give composition of red fire; of green fire. What purpose 
does each ingredient serve ? 



CHAPTER XXI 

THE MAGNESIUM FAMILY 

Outline — 

1. Members of the Family and Their Eelation. 

2. Magnesium. 

(a) Natural Compounds. 

(b) Preparation. 

(c) Properties. 

(d) Uses. 

(e) Compounds. 

3. Zinc. 

(a) Historical. 

(b) Occurrence. 

(c) Properties. 

(d) Uses. 

(e) Compounds. 

4. Mercury. 

(a) History and Old Ideas of. 

(b) Occurrence of. 

(c) Characteristics. 

(d) Uses. 

(e) Compounds — Calomel. 

Corrosive Sublimate. 
Fulminate and Others. 
Exercises for Review. 

1. Members of the Family. — Belonging to this group 
of metals are magnesium, zinc, cadmium and mercury. 
Their atomic weights range from 24 for magnesium to 
200 for mercury. Their chemical activities differ about 
as much. Magnesium is well up in the series and will 
set free hydrogen from water boiling hot, while mer- 
cury will not even do this from acids. 

230 



THE MAGNESIUM FAMILY 231 

2. Magnesium. — Natural Compounds. — Some very in- 
teresting compounds of magnesium occur in nature; 
among these are talc or soapstone, asbestos, and meer- 
schaum. Their uses are familiar. 

Preparation of Magnesium. — Like most of the metals 
already studied magnesium is prepared by the elec- 
trolysis of some compound, in this case a natural com- 
pound of potassium and magnesium chloride. Not a 
great deal is produced, possibly eighteen or twenty tons 
a year. 

Properties of Magnesium. — As already stated it ranks 
high in the series of metals in electropositive character, 
hence displaces hydrogen from dilute acids vigorously. 
It is steel gray in color, has a specific gravity of 1.75. 
tarnishes slowly in the air. Heated somewhat it may 
be drawn into wires and rolled into ribbons in which 
form it is commonly seen. Cold, it may be ground into 
a powder and is also frequently seeil in this form. It 
ignites readily in a Bunsen flame and burns rapidly 
and brilliantly in the air, with a white light, rich in 
actinic rays. By this we mean chemical rays. Sunlight 
contains not only heat and light rays, but chemical rays 
as well. It is the last that bring about the changes in 
a photographic plate and many other things with which 
we are familiar. 

Uses of Magnesium. — To a limited extent it is used in 
various ways in the chemical laboratory. Its most ex- 
tensive use is in flashlight photography. Flashlight 
powders contain magnesium powder mixed with nearly 
twice the amount of potassium chlorate. Naturally, 
therefore, they are dangerous and must be handled with 
care. An alloy of magnesium called magnalium con- 
sisting of aluminum and magnesium is now being made 



232 CHEMISTRY FOR NURSES 

for use in aeroplanes and elsewhere where a light, tena 
cious metal is desired. 

Compounds of Magnesium. — Magnesium Oxide, MgO. — 
This is sold under the name of magnesia. It is a light, 
pure white, powder, basic in character, of very high 
melting point and very poor conductor of heat. It is 
used extensively for lining crucibles and covering hot 
water and steam pipes in buildings and conduits. For 
the latter use it is generally mixed with about 20 per 
cent of asbestos. 

Some Other Compounds. — Magnesium carbonate, pre- 
pared in the laboratory, is a mixture of carbonate and 
hydroxide, thus being a basic salt: MgC0 3 .Mg(HO) 2 o 
It is a white powder often used in tooth-pastes and as 
a silver polish. Magnesium chloride has been men- 
tioned already as a very deliquescent compound and the 
cause of table salt becoming damp in wet weather. 
Magnesium sulphate, MgS0 4 .7H 2 0, is sold under the 
name of Epsom salts. Its use in medicine is well known. 
It is also used in adding weight to cotton goods. 

3. Zinc, Zn, 65.4. — In order of activity zinc follows 
magnesium and is next to it in density also. It was not 
known as a metal to the ancient philosophers, but a 
natural compound of it was, and it was this fused with 
copper that gave them their brass and led them to be- 
lieve in the possibility of transmuting copper into gold. 

Occurrence of Zinc. — The greatest zinc-producing re- 
gion of the United States is what is known as the Jop- 
lin District in southwest Missouri. It embraces an ex- 
tensive area including a portion of southeast Kansas 
and northeast Oklahoma. The ore found there is in the 
form of a sulphide, ZnS, called by the miners, "jack." 
Unlike the metals we have been studying zinc is not re- 



THE MAGNESIUM FAMILY 233 

duced electrolytically but by means of carbon. The ore is 
roasted, which converts it into an oxide as shown in the 
equation, 

2ZnS + 30 2 -> 2ZnO + 2S0 2 

Then the oxide is mixed with crushed coke and heated, 
whereupon the zinc distills out in the form of a vapor 
and is condensed. 

ZnO + C -> CO + Zn 

Properties of Zinc. — It is a bluish gray metal, some- 
what brittle at ordinary temperatures, malleable be- 
tween 125° and 150° C, with a melting point of about 
420 and boiling point of 950. It tarnishes only slightly 
in the air and the protective covering thus formed pre- 
vents further action of the air. It is not high enough in 
the electrochemical series to set free hydrogen from 
water, but it does readily from dilute acids. It is a 
poor conductor of heat and electricity. 

Uses of Zinc. — On account of the last named property 
it is often used beneath and behind stoves to protect 
floors and partitions from the heat, also in refrigerators 
for a lining for the same reason. In most dry cells zinc 
is the container and serves as the positive element while 
a carbon stick is the negative. Its most extensive use 
is possibly in what is called galvanized iron. This is 
iron which has been perfectly cleaned and then dipped 
into molten zinc. A protective coating of the zinc ad- 
heres to the iron. This is used for a very great variety 
of purposes. Nearly all fencing is now made of galva- 
nized wire ; also windmills, stock drinking-troughs, grana- 
ries, cornice work, guttering, down spouts, as well as 



234 CHEMISTRY FOR NURSES 

many other things in everyday life. Many alloys 
of zinc of very great value are also known. An alloy 
is a mixture of two or more metals: sometimes the re- 
sulting product is so different from the metals forming 
it that it would almost seem as though a chemical change 
had taken place. Among these alloys of zinc we would 
mention brass, composed of copper and zinc, and Ger- 
man silver made from copper, zinc and nickel. Some 
varieties of bronze also contain zinc although usually it 
has only copper and tin. 

Zinc Oxide, ZnO. — This is a product obtained inci- 
dentally in many smelters from ores containing a very 
small percentage of zinc. It is yellow when hot but 
white when cold. Its most extensive use is as a paint 
and is sold under the name of zinc white. It has some 
advantages over lead paints in that it is not discolored 
by hydrogen sulphide gas. It is also used somewhat in 
the form of an ointment as a remedy for skin diseases 
and eruptions. 

Zinc Sulphate, ZnSO±.7H 2 0. — Commercially this is 
known as white vitriol. It may be obtained by treating 
zinc with dilute sulphuric acid. It is a white compound, 
readily giving up its water of combination. It is used 
to some extent as a mordant in dyeing cotton goods. A 
mordant is a substance which has the power of setting 
colors in dyeing. Just what the chemical action is is 
not well understood. 

Zinc Chloride, ZnCl 2 . — Zinc chloride is a white salt, 
exceedingly deliquescent, prepared by treating zinc 
with hydrochloric acid. It is used by tinners to obtain 
a clean surface upon the article to be soldered before 
dropping the solder. When hot, zinc chloride has the 
remarkable property of being able to dissolve cellulose; 
it is by this means that parchment is made. 



THE MAGNESIUM FAMILY 235 

4. Mercury, Hg, 200. — So far as any records go, mer- 
cury was first prepared by Theophrastus, 300 b. a, who 
named it liquid silver. It has always since that time 
been an object of interest and has entered into various 
theories as to matter, as we have already seen. It is 
found in nature in the form of a sulphide, called cin- 
nabar, to some extent in California, but most abun- 
dantly in Spain. 

Characteristics of Mercury. — Mercury is what metal- 
lurgists call a noble metal, which means that it can be 
obtained from its ores by heat alone without any re- 
ducing agent. It is the only metal liquid at ordinary 
temperatures, solidifies at -39° C. and boils at 357°, 
It has a specific gravity of 13.6 so that lead, iron and 
most of the common metals and alloys float upon it as 
corks on water. It does not tarnish in the air. One of 
its most remarkable properties is that of being able to 
dissolve many of the other metals. Such solutions or 
mixtures we call amalgams, and are really alloys of 
which one metal is always mercury. 

Uses of Mercury. — It is commonly used in thermom- 
eters and barometers: in the former because its rate 
of expansion is high and uniform through a long range, 
also of high boiling point. In dentistry it is used in 
making amalgams with silver and tin for filling cavi- 
ties in teeth. For electric batteries the zinc electrode is 
often amalgamated to decrease the rapidity of destruc- 
tion of the zinc ; and in a cheap grade of mirrors a tin 
amalgam is used. One very extensive use is for the re- 
covery of gold in placer and dredge boat mining. 

Calomel, Mercurous Chloride, Hg 2 Cl 2 . — This is a well- 
known white powder used as a purgative in medicine. 
Like all mercury compounds it is poisonous, but not 



236 CHEMISTRY FOR NURSES 

being soluble its action is much slower. Except with 
precautions, salivation is apt to follow its continued use. 
This is prevented now by the admixture of small quan- 
tities of soda with the calomel. The purpose of this is to 
combine with the hydrochloric acid of the stomach and 
thus not allow of its reaction with the calomel 

HC1 + NaHC0 3 -> NaCl + H 2 + C0 2 

This equation shows that the soda converts the hy- 
drochloric acid into common salt, a very stable body 
which will not yield its chlorine to the calomel. We 
have seen heretofore that mercurous chloride is an un- 
saturated compound; what it probably does, therefore, 
in the presence of any acid in the stomach, whether that 
be hydrochloric or acetic from pickles or citric from 
lemons or grape fruit, is to take up another acid ele- 
ment or group to form a saturated compound. This 
converts it into a mercuric compound which is much 
more soluble than the calomel and therefore is taken up 
by the system rapidly and affects primarily the sali- 
vary glands and secondarily the teeth. We can see the 
reason, therefore, for cautioning patients when taking 
calomel not to use acid foods. 

Mercuric Chloride, Corrosive Sublimate, HgCl 2 . — This 
is also a white compound, but crystalline in character. 
When heated it vaporizes without melting, which is 
called sublimation, hence the name of the compound. 
It is exceedingly poisonous ; the best antidote is prob- 
ably the white of egg with which it forms a coagulum, 
not readily soluble. Milk will do, but not nearly so 
well. It is used as an antiseptic in sterilizing surgical 
instruments and upon bandages and applications to 



THE MAGNESIUM FAMILY 237 

wounds. It is not poisonous to the body used in this 
way. Very dilute solutions applied to the scalp occa- 
sionally are said to prevent dandruff and constitute 
one of the ingredients of most hair tonics. Horticul- 
turists also sometimes soak potatoes they are preparing 
to plant in a very dilute solution of corrosive subli- 
mate for a short time in order to destroy what is known 
as "scab," a disease making the tuber rough upon the 
outside. 

Mercuric Fulminate, Hg(ONC) 2 . — This compound has 
been mentioned in connection with explosives as the 
detonator needed with most of them for ignition. 

Other Compounds. — Vermilion is the artificial sul- 
phide: it is of a brilliant red color, used as a pigment 
in various cases. Mercuric oxide, HgO, occurs in the 
red and yellow variety. There is difference only in the 
size of the particles, the yellow consisting of much the 
finer. It is the yellow oxide generally used in medicine, 
for ointments mainly. Its action is probably mainly 
antiseptic. 

Exercises for Review 

1. What metals belong to the magnesium family? Which is 
the lightest? The heaviest? The most active? The least ac- 
tive? 

2. Name the natural compounds of magnesium. What are 
their chief uses ? 

3. How is magnesium prepared? What is the annual output? 

4. Give the chief properties of magnesium. What are actinic 
rays? 

5. What are the chief uses of magnesium? Why are flash- 
light powders dangerous? What is magnalium? 

6. What is magnesia? Chief uses? Give some medical uses. 

7. Name three other magnesium compounds. Give their uses. 
What annoyance does the chloride cause in our homes? 

8. What was the earliest use of zinc made by the ancients? 



238 CHEMISTRY FOR NURSES 

9. Where is zinc found in America ? In what form? Called 
what ? 

10. How is zinc reduced from its ores differently from other 
metals already studied? 

11. Give chief properties of zinc. Which one of these adds 
its chief commercial value? 

12. Is it safe to make lemonade and allow to stand in a gal- 
vanized iron vessel? Why do you say so? 

13. What is galvanized iron? How used? 

14. Name some alloys of zinc. What is an alloy? What is 
German silver used for? 

15. What is zinc white? Its chief use? What advantage has 
it? 

16. What medical use has zinc oxide? Why so used? 

17. What is a mordant? Name one. 

18. Give some interesting uses of zinc chloride. 

19. When was mercury first made? What are some of the 
old theories regarding it? 

20. What is a noble metal? Give chief properties of mer- 
cury. 

21. What is an amalgam? Give three uses of amalgams. 

22. Why is mercury used in thermometers? Why in barom- 
eters? 

23. What is calomel? Its use? Its danger? How obviated? 

24. What is corrosive sublimate? Why so named? What is 
its antidote? 

25. Give chief uses of corrosive sublimate. 

26. What is chief use of mercuric fulminate? What is a de- 
tonator? 

27. Name two other compounds of mercury. What uses have 
they? 



CHAPTER XXII 

THE ALUMINUM FAMILY 

Outline — 

1. The Aluminum Family. 

2. Occurrence of Aluminum in Nature. 

(a) Relative Abundance. 

(b) Natural Compounds. 

3. Precious Stones. 

(a) Names and Composition. 

(b) Synthetic Stones. 

4. Other Natural Compounds. 

5. Manufacture of Aluminum. 

6. Properties of Aluminum. 

7. Uses of. 

(a) As a Metal. 

(b) In Alloys. 

(c) Thermit. 

8. Alums. 

(a) Kinds of Alums. 

(b) Uses of. 

9. Aluminum Hydroxide. 
Exercises for Eeview. 

1. Members of the Family. — In this group aluniinuin 
is the only element ^ye shall study. Boron belongs here 
and ^ye have already studied one compound of it under 
sodium. The other members of the family are rare and 
unimportant. Boric acid, H 3 B0 3 , is a mild antiseptic, 
and in solution is sometimes used as a medicine for in- 
flamed eyes. 

2. Occurrence of Aluminum. — Although never found 
free in nature aluminum is third in abundance of all 

239 



240 CHEMISTRY FOR NURSES 

the elements, constituting about 8 per cent of the en- 
tire amount. It is found in all clays, as well as felspars 
from which clays are formed, also in mica, used in 
stoves often under the misnomer of isinglass. Bauxite, 
a hydrated oxide, fuller's earth, corundum, next to the 
diamond in hardness, kaolin, emery, and a number of 
other familiar substances are compounds of aluminum. 

3. Precious Stones. — The garnet is a calcium aluminum 
silicate with the formula, Ca 3 Al 2 (Si0 4 ) 3 . The ruby and 
sapphire are oxides of aluminum colored by minute 
quantities of other metallic oxides. At the present 
time they are being manufactured in large quantities 
by fusing artificially prepared aluminum oxide and col- 
oring them as in nature. The white sapphire is the 
same compound, uncolored. It is said that between 
nine and ten million carats of rubies and about half as 
many sapphires are manufactured annually. They have 
all the characteristics of the natural stones without the 
defects, hence are even better. They are often spoken 
of as synthetic sapphires. 

4. Other Natural Compounds. — Emery. — This is an 
impure oxide of great hardness, used in the form of 
wheels, whetstones and other ways as an abrasive. Ful- 
ler's earth is a silicate of aluminum used to absorb col- 
oring matter from oils and other articles of commerce. 

Kaolin. — Kaolin is a pure, white clay. Mixed with 
felspar it is used in making porcelain and chinaware. 
Ordinary pottery ware is made from colored clays, and 
baked. To glaze the surface salt is thrown into the kiln 
when it combines with the surface materials forming a 
silicate and filling the pores. 

5. Preparation of Aluminum for Commerce. — Like 



THE ALUMINUM FAMILY 



241 



most of the metals studied up to this time it is obtained 
by electrolysis, at places where cheap water power may 
be had for the generation of electric current. Fig. 37 will 
show the general method. The anode consists of a 
number of heavy carbon rods while the cathode is the 
furnace itself. A compound called cryolite, meaning 
ice stone, and so called because of its very low melting 
point, is put into the furnace and melted. Then bauxite, 
a purified oxide of aluminum, is added. The cryolite 
dissolves the bauxite as salt would dissolve in water 
and the heavy current is passed through. The aluminum 
collects at the bottom and is drawn off at intervals. 




Fig. 37. Manufacture of aluminum. 

As the bauxite is used, more is added to take its place 
so that the process is continuous. 

6. Properties of Aluminum. — It is a white metal of 
low specific gravity, 2.6, being only about one-third as 
heavy as iron. It is malleable and ductile, but lacking 
in tensile strength. It is an excellent conductor of heat 
and electricity, being surpassed only by copper and 
silver. It does not tarnish appreciably in the air, is 
below magnesium in electropositive character, yet dis- 
places hydrogen from hydrochloric acid rapidly: w T ith 
sulphuric very slightly. It is attacked strongly by the 
alkalies forming compounds called aluminates. 



242 CHEMISTRY FOR NURSES 

7. Uses of Aluminum. — On account of its conductiv- 
ity it is used extensively for electric cables and feed 
wires. Although not quite as good as copper, from the 
fact that the size of the wire determines partly the con- 
ductivity and as from a given weight of aluminum a 
much larger cable can be made than from the same 
weight of copper, aluminum has advantages even over 
copper. Perhaps the most extensive use is by steel 
manufacturers to prevent blowholes in their ingots. 
Aluminum has the power of combining with the gases 
formed in the manufacture of steel and thus preventing 
their remaining in the ingot. If not removed, when 
these ingots are rolled into steel rails or other objects 
the gas bubbles make imperfections and weak spots 
which formerly caused great annoyance. It is being 
manufactured largely into cooking vessels and is nearly 
ideal for that purpose. Being an excellent conductor 
the entire vessel is uniformly heated, while in one of 
" granite' ' ware of poor conductivity, the bottom is 
much hotter. Naturally therefore, foods do not scorch 
nearly as readily in aluminum vessels. Moreover they 
are light, do not tarnish readily, are not attacked by 
the weak acids of food products and are reasonably 
easy to clean. Ground to a fine powder aluminum is 
used in oil as a paint for decoration of radiators, as 
well as many outside objects of metallic character, no- 
tably mail boxes, penny weight machines, and the like. 

Another very valuable application is in what is known 
as thermit. This is a mixture of ferric oxide and pow- 
dered aluminum. It is put into a crucible of suitable 
size, is primed by a small quantity of powdered 
magnesium, and lighted. The magnesium in burning 
generates sufficient heat to cause the more electro- 



THE ALUMINUM FAMILY 243 

positive aluminum to begin combining with the oxygen 
of the ferric oxide ; the action continues and a heat of 
3,000° or over is produced. The aluminum oxide 
formed is melted and rises to the top while the molten 
iron settles to the bottom and may be drawn off as de- 
sired. (See Fig. 38.) The process is a patented one, but 
is being used extensively in welding all sorts of broken 
castings, even of the largest character, such as the pro- 
peller shafts in large engines and steamships. 

Aluminum Alloys. — There are several alloys of 




Fig. 38. — Thermit apparatus. 

aluminum of much value. Magnalium containing a 
small percentage of magnesium has much greater tenac- 
ity than pure aluminum. Aluminum bronze is an alloy 
of copper and aluminum, the copper not over 10 per 
cent. It resembles gold more or less closely, is per- 
manent in the air and has many valuable applications, 
especially in novelty goods. Another aluminum bronze 
contains a very small percentage of copper and is even 
whiter than aluminum itself, resembling silver closely. 
It is even easier to keep bright than silver and is used 
for some household articles instead of silver. 



244 CHEMISTRY FOR NURSES 

8. Alums. — Alums are double sulphates, that is sul- 
phates of two metals, one of which originally was 
aluminum. But as there are several other elements 
which may take the place of aluminum in making these 
double sulphates and give compounds with all the gen- 
eral characteristics, the term alum has come to be ap- 
plied to all of them. So, any trivalent element, like iron 
or chromium may be substituted for the aluminum and 
any univalent element or group, - like sodium or am- 
monium, may be the other part. Common alum is potas- 
sium aluminum sulphate, K 2 Al 2 (SOJ 4 .24H 2 0. If this 
is heated to expel the water of combination we have 
what is called burnt alum. It is a mild caustic and is 
often used medicinally in that way. 

Uses of Alum. — As one of the constituents of baking 
powder alum has already been mentioned. Often how- 
ever, aluminum sulphate is used instead of alum and is 
sold to the trade under the name C. T. S. meaning cream 
tartar substitute. Aluminum sulphate is also used as al- 
ready explained in settling muddy waters for city sup- 
plies. We can now understand better what happens by 
noticing the chemical action as shown by the equation: 

A1 2 (S0 4 ) 3 + 3Ca(HO) 2 -> Al 2 (HO) 6 + 3CaS0 4 

The aluminum hydroxide is gelatinous in character 
and has the power of coagulating and carrying down 
the sediment. It will be noticed further from the equa- 
tion that calcium sulphate is added to the water, so 
that while we are removing the foreign matter we have 
increased the permanent hardness. This, however, is 
unavoidable. 

Aluminum Hydroxide, Al 2 (HO) R . — This is a white 



THE ALUMINUM FAMILY 245 

solid obtained whenever any alkali is added to a solution 
of an aluminum salt. It is this that serves as the coagu- 
lant spoken of in the preceding section. There are 
many ways in which aluminum hydroxide is used to 
some extent. Owing to the fact that it has the power of 
absorbing foreign matter, if it is precipitated in a solu- 
tion of a dye it has the power of absorbing the coloring 
matter and carrying it down with it. Such precipitates 
are often dried and made into various colored tube- 
paints called lakes used by artists. In the same way pa- 
per is often sized that it may be suitable for ink ; and dyes 
are set in fabrics by this method. Aluminum hydroxide 
is precipitated Avithin the fibers of the cloth and this 
seizes the coloring matter and holds or fixes it. Fab- 
rics are sometimes waterproofed by dipping in a solu- 
tion of certain aluminum compounds and then heating 
by means of steam. The aluminum compound is de- 
composed with the formation of the hydroxide in the 
fibers. When dried, being an insoluble compound, it 
renders the cloth largely waterproof. 

Exercises for Review 

1. Name two members of the aluminum family. What com- 
pound of one have we already studied? 

2. What can you say of the abundance of aluminum? Name 
several natural compounds. 

3. Name four precious stones, compounds of aluminum. What 
is their composition? 

4. What is a synthetic ruby? A white sapphire? Why are 
they better than the natural stones? 

5. What is emery? Give its uses. 

6. What is kaolin? Its uses? From what is pottery made? 
How glazed? 

7. Describe the method of manufacturing aluminum. What 
is bauxite? What is the purpose of the cryolite? 



246 CHEMISTRY FOR NURSES 

8. Give the chief properties of aluminum. 

9. What is the most extensive use of aluminum? 

10. Why is it used instead of copper for cables? What ad- 
vantage has aluminum as a cooking vessel? 

11. Describe the process of welding by thermit. 

12. Name four alloys of aluminum and give uses. 

13. What is an alum? What is common alum? What is 
burnt alum? 

14. Give important uses of aluminum sulphate. How does it 
clarify water? 

15. How does aluminum hydroxide serve as a mordant? 

16. How are fabrics sometimes waterproofed with aluminum 
hydroxide? 



CHAPTER XXIII 

THE COPPER FAMILY 

Outline — 

1. Members of the Copper Group. 

2. Copper Deposits in America. 

(a) Lake Kegion. 

(b) Western States. 

3. Characteristics of Copper. 

4. Uses of Copper. 

5. Copper Sulphate. 

(a) Source of Commercial Supply. 

(b) Valuable Uses. 

6. Silver, Characteristics. 

7. Uses of Silver. 

8. Compounds of Silver. 

(a) Silver Nitrate. 

(b) Lunar Caustic. 

(c) Silver Bromide. 

(d) Silver Chloride. 
Exercises for Bevievr. 

1. Members of the Group. — The copper group con- 
sists of copper, silver and gold, all familiar metals and 
known from remote antiquity. This is because they 
all are found free in nature and easily worked. Of the 
three, copper is the most active chemically, then silver 
and gold. The last is not soluble in any single acid, 
but in the mixture of hydrochloric and nitric, known 
as aqua regia. 

2. Copper Deposits. — The oldest mines in America are 
those of the Lake Michigan and Lake Superior region. 
They were known to the prehistoric tribes and the 

247 



248 CHEMISTRY FOR NURSES 

sheets of pure copper were stripped off from the out- 
cropping layers and beaten into various cups and vessels. 
These have often been found in the great mounds left 
by those people. These deposits are still valuable, the 
mines of Calumet and Hecla being famous. Some are 
now at a depth of a mile or more and are being worked 
constantly. Some of the Western States, Montana, 
Colorado, New Mexico, and Arizona, are also great cop- 
per producers, but in those states the metal is in the 
form of ores and not native copper. With it are usu- 
ally associated several other metals, gold, silver and 
sometimes zinc and lead, as well as iron which is not 
recovered. 

3. Characteristics of Copper. — Copper is a red metal, 
very tenacious, malleable, an excellent conductor of 
heat and electricity, surpassed only by silver, It has 
a melting point of nearly 1100° C. It tarnishes in the 
air, ultimately forming, if moisture is present, the basic 
carbonate, CuC0 3 .Cu(HO) 2 , a greenish compound. 

4. Use's of Copper. — On account of its excellent con- 
ductivity, it is used extensively for electric cables, tel- 
ephone wires, electric wiring for buildings, etc. A com- 
parison with aluminum in some of these respects has 
been mentioned elsewhere. Because of heat conductiv- 
ity it has long been used for cooking vessels wherever 
acids were not present. Thus in candy factories the 
kettles are of copper because of the less probability of 
scorching the sirup, owing to the distribution of the 
heat over all the surface: stills, evaporating pans and 
a great variety of similar uses come for the same rea- 
son. In the household, copper is not practicable be 
cause readily attacked by weak acids like acetic and 
those found in fruits. In large establishments, like asy- 
lums, penitentiaries, and the like, or where quick serv- 



THE COPPER FAMILY 249 

ice is essential, such as in the Harvey system of eating 
houses or other railway restaurants, copper vessels are 
used but are covered with a thin layer of tin. This 
protects the copper from the acids and renders the use 
of the copper vessel perfectly safe. Copper is also used 
as sheathing for vessels as it is not readily attacked by 
sea water; for roofing, gutters, down spouts, and the 
like, being much more permanent than galvanized iron. 
Its alloys are also very important. Our coins contain 
copper. Brass is copper and zinc, in varying propor- 
tions according to the use to be made of it. Bronze has 
been mentioned previously; also the alloys with 
aluminum. 

5. Blue Vitriol, Copper Sulphate, CuS0 4 .5H 2 0.— This 
familiar compound is often sold under the name of 
blue stone. It is a by-product mainly of some of our 
great smelters, being obtained in the refining of gold 
and silver ores. Formerly, the Argentine smelter at 
Kansas City produced monthly as much as 1,800 tons, 
with a valuation of nearly $200,000; at the present 
time the refineries of Omaha and Denver are doing the 
work formerly done at Kansas City. Blue vitriol is 
used in one kind of wet battery and is one of the most 
efficient made. Mention has already been made of its 
use in preventing the growth of algas in lakes used as 
city water supplies. It is employed extensively in mak- 
ing Bordeaux mixture for spraying fruit trees and es- 
pecially grapes, for the destruction of various fungi. 
One of the most extensive uses at the present time is 
for electroplating and electrotyping. The plates from 
which the pages of books are printed are of copper and 
what are known as electrotypes. The "lead" type after 
being proofread is put into page form. An impression 
of this is taken in a sheet of wax and this covered on 



250 



CHEMISTRY FOR NURSES 



the one side with fine graphite to render it a conductor. 
This is now suspended in a copper sulphate bath upon 
the cathode, and a current applied. To keep the solu- 
tion up to the original strength a sheet of copper is 
hung upon the anode. The copper is carried to the 
cathode and deposited upon the graphite giving an ex- 
act copy of the lead type. When the thickness has 
reached about that of a visiting card the sheet is re- 
moved from the bath, carefully washed and dried, and 
molten type metal poured upon the back to give in- 
creased thickness and strength. This melts the wax off 




V-rnr 




.copper _ — -wax 



T 



CuS0 4 joluhorj 



4&ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ2ZZ2Z2Z 



Fig. 39. — Making an electrotype. 

and leaves a page of copper type, which from its great 
toughness may be used in printing hundreds of thou- 
sands of copies if desired. Patent advertisements in 
our newspapers, which make the rounds of the country 
from city to city, are furnished to the papers in the 
same way. (See Fig. 39.) 

6. Silver, Ag, 107.88. — Silver is so well known that 
little need be said of it in a work of this size. In pure 
air it does not tarnish, but from the fact that usually 
there is some hydrogen sulphide present, silverware in 
our homes does turn dark. This discoloration is silver 



THE COPPER FAMILY 251 

sulphide: there are various polishes for removing it, 
but if the article is not too large to place in an aluminum 
vessel it may be cleaned most easily in that way. Cover 
it with water, add a small amount of salt, though even 
this is not necessary, and boil for two or three minutes. 
The aluminum being more electropositive, removes the 
sulphur from the silver and leaves it untarnished. For 
spoons, knives and other small articles this is a most 
satisfactory way. 

7. Uses of Silver. — Little need be said upon this topic 
as they are so well known. Silver coins of the United 
States are 900 parts silver to 100 of copper: those of 
Great Britain are 925 silver to 75 of copper, a little 
richer than our own. When silverware is spoken of as 
" Sterling' ' it is not pure silver as many suppose, but 
of the fineness of English coins, that is, 92.5 per cent 
and the remainder copper. Silver may be very easily 
reduced from its compounds ; advantage is taken of this 
fact in depositing it upon glass for all high grade mir- 
rors. They are far superior to the tin amalgam mir- 
rors spoken of elsewhere, which are inclined to blister. 
It is in this way that the silver deposit is obtained upon 
the inner surfaces of the vacuum bottle in the thermos 
bottles now in common use. The student may easily 
make the experiment by putting a few cubic centimeters 
of silver nitrate solution into a test tube, adding ammo- 
nia water, drop by drop, until the brown precipitate 
which forms at first has redissolved, then adding a 
small amount of tartaric acid and heating. The silver 
will deposit firmly upon the inner surface of the test 
tube if clean. 

8. Silver Compounds. — One of the more common is 
silver nitrate, AgN0 3 . It is a white, crystalline solid 
made by dissolving silver in nitric acid. An impure 



252 CHEMISTRY FOR NURSES 

form, containing a small percentage of silver chloride, 
is sold in stick form at the drug stores under the name 
of " lunar caustic. " It is a mild cauterant and is fre- 
quently used in removing warts from the hands, some- 
times for ulcerations of the mouth and throat, as an 
antiseptic in certain wounds, as dog bites, etc. Most of 
the hair dyes contain silver nitrate as the active prin- 
ciple, from the fact that when exposed to light, espe- 
cially in contact with organic matter, it turns dark. 
Silver nitrate is used in many indelible inks for the 
same reason. 

In photography silver chloride is used mainly on 
printing out papers, such as those the photographer 
shows in his proofs. Silver bromide is generally used 
both on plates and films and also on the permanent pic- 
ture. These compounds are prepared from silver ni- 
trate by treatment with potassium or ammonium bro- 
mide for the bromide and with common salt for the 
chloride. 

Exercises for Review 

1. Name the members of the copper group. Why have they 
been known so long? 

2. State chief facts regarding the oldest mines in America. 

3. In what form is copper found in the Western states? 

4. Give chief properties of copper. 

5. Name the important uses of copper and state why so used. 

6. Why is copper not used in most households as a cooking 
vessel? 

7. Brass kettles are sometimes used to make pickles in. Why? 
What objection? 

8. Give two other names for copper sulphate. How is it ob- 
tained for commerce? 

9. Describe the process of electrotyping. 

10. For what is Bordeaux mixture used? Give other uses for 
blue vitriol, 



THE COPPER FAMILY 253 

11. What is the discoloration on silverware? How may it be 
removed easily? 

12. Why do eggs tarnish a silver spoon so badly? 

13. What is Sterling silver? 

14. How are high grade mirrors made? 

15. What is lunar caustic? How different from silver ni- 
trate ? 

16. Give some medical uses of silver nitrate. Some other 
uses. What is the chemical reason underlying each use? 

17. Name .some other compounds of silver and give use. 



CHAPTER XXIV 
THE LEAD FAMILY 

Outline — • 

1. Members of the Family. 

(a) The Metals. 

(b) Nonmetals Belonging. 

2. Deposits of Tin. 

(a) Oldest Deposits. 

(b) Others Now in Use. 

3. Characteristics of Tin. 

4. Uses of Tin. 

5. Compounds of Tin. 

6. Lead, Characteristics of. 

7. Uses of Lead. 

(a) As an Alloy. 

(b) In Other Forms. 

8. Compounds of Lead. 

(a) Lead Acetate. 

(b) White Lead. 

(c) Chrome Yellow. 

(d) The Oxides. 
Exercises for Eeview. 

1. Members of the Group. — There are only two com- 
mon metals belonging to this group, tin and lead. Car- 
bon and silicon also belong in the family, but not being 
metals they are treated elsewhere. Tin is the more 
active of the two. 

2. Occurrence of Tin. — It has been known for cen- 
turies and was brought from the mines of Cornwall, 
England, by the ancient Phoenicians. These mines are 
still productive but more is obtained from the East 

254 



THE LEAD FAMILY 255 

Indies and Bolivia. There are no paying deposits at 
present in the United States. 

3. Characteristics of Tin. — Its atomic weight is 119. 
It is a soft metal, white in color, malleable, with a 
melting point of 232. It is not affected by the air nor 
by vegetable and fruit acids. Hydrochloric acid is at- 
tacked by it setting free hydrogen while strong nitric 
is rapidly decomposed. 

4. Uses of Tin. — The most familiar use of tin is for 
making tin " plate' ' which is steel covered by a thin 
layer of tin made by dipping into molten tin, as gal- 
vanized iron is in zinc. The use of tin plate now is 
mainly for "tin" cans, though formerly tin cups, and 
cooking vessels of all sorts were common. Ordinary 
solder is an alloy of tin and lead about half and half. 

5. Compounds of Tin. — Scarcely any of these are of 
interest to the general student. At least two are used 
in mordanting and one, stannic acid, is used in weight- 
ing silk goods. It is said that most silks are weighted, 
sometimes very greatly. 

6. Characteristics of Lead, Atomic Weight, 207.1. — 
Lead is a dark grayish metal, soft and malleable; is 
only attacked slightly by the air and this covering serves 
as a protection, much as a coat of paint. It has a 
melting point of 325° C. and specific gravity of 11.38. 
It has very little power of decomposing acids, from the 
fact that it is next to hydrogen in the scale, hence but 
little more positive than hydrogen itself. Its salts are 
all poisonous and form what are known as accumulative 
poisons, that is, the system is unable to eliminate them. 
Persons working with lead compounds therefore are apt 
sooner or later to be seriously affected by the poison. 

7. Uses of Lead. — It is used in sheet form as linings 
for sulphuric acid chambers in the manufacture of that 



256 CHEMISTRY FOR NURSES 

acid, for sinks, and in various other places where acids 
are being used. An extensive use is in the form of pipe 
for covering 1 underground cables of telephone and tele- 
graph wires, as well as overhead cables: waste pipes in 
the plumbing of all houses and buildings, and various 
other ways. As an alloy in solder it has been mentioned, 
also in type metal. 

8. Compounds. — Lead Acetate, Pb(C 2 H 3 2 ) 2 .3H 2 0. — 
This is commonly sold at drug stores under the name of 
sugar of lead. It is a white crystalline salt with an un- 
pleasant, metallic, sweet taste. Like all lead salts, it 
is very poisonous. It is often recommended for applica- 
tion in cases of "poison ivy. " 

White Lead, 2PbC0 3 .Pb (HO) 2 .— It will be observed 
that this is a basic salt, being a mixture of the carbon- 
ate and a base, lead hydroxide. It is the oldest white 
paint known and used extensively. One objection is 
the danger of poisoning to which the laborers in the 
factory are subjected as well as the painter who applies 
it. Another objection mentioned elsewhere is that in 
the presence of hydrogen sulphide it is darkened be- 
cause of the fact that the lead carbonate is being 
changed into the sulphide which is black. It is a very 
durable paint, however, and very satisfactory for most 
places. 

Chrome Yellow, PbCr0 4 . — Chemically this compound 
is known as lead chromate. It is the most common 
yellow pigment. 

The Oxides. — There are three oxides of lead. The 
most common one, lead monoxide, PbO, is a by-product 
of the silver refineries. It is a yellowish or brownish 
powder, used extensively for the manufacture of flint 



THE LEAD FAMILY 257 

glass as mentioned elsewhere. Red lead, Pb 3 4 , is a 
bright red powder, used with oil in making tight gas- 
joints in plumbing and in the manufacture of glass. 

Exercises for Review 

1. What metals belong to the lead family? What two non- 
metals? 

2. Name the three best tin producing regions of the world. 

3. Describe tin. Why is it used as a covering for copper cook- 
ing vessels? 

4. W T hy is it used in solder? Why in tin plate? 

5. Name one compound of tin of interest and give use. 

6. Give the chief characteristics of lead. 

7. W 7 hat is a cumulative poison? 

8. Give the chief uses of lead. What alloys have we studied? 

9. What is sugar of lead? Why so called? Its use in medi- 
cine? 

10. What is white lead? Its use? Objections to its use? 

11. W 7 hat is chrome yellow? Its use? 

12. Name two oxides of lead? What are their uses? 



CHAPTER XXV 

IRON AND COMPOUNDS 

Outline — 

1. Distribution of Iron Compounds. 

2. Ores of Iron. 

(a) Composition of. 

(b) Field Tests for. 

3. Varieties of Iron. 

(a) Composition. 

(b) Comparison of Properties. 

4. Varieties of Steel. 

(a) Composition. 

(b) Uses of. 

5. Compounds of Iron. 

6. Tempering Steel. 
Exercises for Eeview. 

1. Occurrence of Iron. — Iron is very widely distrib- 
uted in nature. It is found to a greater or less extent 
in all soils and clays ; nearly all rocks and metallic ores 
also contain more or less iron associated with them. It 
is this that more often gives the brownish or red colors 
observed. Iron is also found in traces in our foods and 
in the hemoglobin of the blood. 

2. Ores of Iron. — The most valuable ore of iron in 
the United States is hematite, Fe 2 3 . A similar com- 
pound, limonite, often called brown hematite, with com- 
position Fe 2 3 3H 2 0, is also found abundantly. In some 
portions of the country magnetic ore, Fe 3 4 , is found 
in considerable quantities. The last of these shows 
faint magnetic properties, while the other two give 

258 



IRON AND COMPOUNDS 259 

respectively red, and yellow or brown, streaks upon an 
unglazed porcelain dish. 

3. Varieties of Iron. — Iron is the most valuable of all 
metals from the fact of its numerous uses in modern 
life. It has three forms, cast iron, wrought iron and 
steel. The first is very brittle, of coarse granular struc- 
ture, containing often as much as 5 per cent of impu- 
rity, mostly carbon. Its melting point is much lowered 
by these impurities. Wrought iron is denser than cast 
iron, is very tough and malleable, and contains not over 
0.2 of one per cent of carbon. Steel varies in amount 
of carbon from about 0.5 to 1.5 per cent. It has the 
property when tempered of taking an edge needed in 
cutting tools and is also of very great tensile strength. 
If wires of the same size, of lead and steel, are tested, 
the former will sustain without breaking only about 
one fortieth what the latter will: and even copper will 
withstand but little more than half what steel will. 

4. Varieties of Steel. — For various purposes small 
amounts of other metals are now alloyed with steel, 
giving certain very desirable properties. Armor plate, 
a variety very tough, and resistant to sea water, is 
made of what is known as nickel steel, containing some- 
times as much as 4 per cent of nickel. For parts of 
automobiles, axles and frames, a chrome steel is used, 
containing small amounts of chromium and vanadium. 
For burglar-proof safes a manganese steel is used con- 
taining 10 or more per cent of manganese. So, other 
varieties are made to meet the various requirements 
made of steel. 

5. Compounds of Iron. — Iron forms a large number of 
compounds, many of them of great interest to the chem- 
ist. Ferric hydroxide, Fe(HO) 3 , has been mentioned as 



260 CHEMISTRY FOR NURSES 

the best antidote for arsenic poisoning. Ferrous sul- 
phate, known as green vitriol, is often used as a disin- 
fectant. Prussian blue is often used in laundry work 
to make the articles appear whiter than they would 
otherwise. It is a complicated salt, known as ferric 
ferrocyanate with a formula Fe 4 (Fe(CN) 6 ) 3 . In large 
laundries, however, coal tar blues have largely taken 
the place of this iron compound. 

6. Tempering Steel. — As stated elsewhere iron con- 
tains more or less iron carbide. By suddenly cooling 
it from a high temperature it is found that the amount 
present is much greater; it is this carbide that permits 
of the steel taking a cutting edge. After cooling sud- 
denly in this way the steel is too brittle and must be 
heated again to a much lower temperature and cooled 
more slowly. By varying this degree of heating dif- 
ferent grades of steel are obtained, suited to different 
kinds of instruments. 

Exercises for Review 

1. What can you say of the distribution of iron compounds? 

2. Name the most valuable ores of iron? Give their com- 
position. 

3. Give some easy field test which might be made for each 
of these ores. 

4. Name the three varieties of iron with differences. 

5. What uses can you mention for cast iron? 

6. Give some uses for wrought iron. 

7. Name three varieties of steel and give uses. 

8. Give some medical use of ferric hydroxide. 

9. How is steel tempered? 



CHAPTER XXVI 
SOME COMMON POISONS 

Outline — 

1. Preliminary Statement. 

2. Classification of the Poisons. 

3. Individual Susceptibility. 

4. The Strong Acids. 

(a) Symptoms. 

(b) Antidotes and Treatment. 

5. The Alkalies. 

(a) Symptoms. 

(b) Treatment. 

6. Nonmetallic Elements. 

(a) Effects of. 

(b) Treatment. 

7. Metallic Compounds. 

(a) Symptoms. 

(b) Antidotes and Treatment. 

8. Vegetable Compounds. 

(a) Effects and Symptoms. 

(b) Treatment. 

9. Animal Products. 

(a) Uses and Effects. 

10. Neurotics. 
Exercises for Eeview. 

1. Preliminary Statement. — Most of the poisons which 
will be mentioned in this chapter have been studied in 
other places in the book but rather from another view- 
point than their toxic properties, although those have 
been mentioned. It seems well to have them all put 
together in case a hasty reference is desired. 

261 



262 CHEMISTRY FOR NURSES 

2. Classification of Poisons. — There seems no way 
which is satisfactory in every particular for classify- 
ing the various poisons. Several different methods have 
been proposed, all of which are open to some objection. 
For our brief study we shall take them up as to their 
general effect upon the body. The following outline 
will give the plan. 

A. Irritants Proper. 

I. Strong Acids. 

1. Sulphuric. 

2. Nitric. 

3. Hydrochloric. 

II. Strong Alkalies. 

1. Caustic Soda. 

2. Caustic Potash. 

3. Ammonia. 

B. Specific Irritants. 

I. Nonmetallic Elements. 

1. Phosphorus. 

2. Chlorine. 

3. Bromine. 

4. Iodine. 

II. Metallic Compounds. 

1. Arsenic Compounds. 

2. Antimony Compounds. 

3. Mercury Salts. 

4. Lead Acetate, White Lead, and Others. 

5. Copper Salts. 

6. Zinc Salts. 

III. Vegetable Compounds. 

1. Oxalic Acid. 

2. Phenol. 

3. Croton Oil. 

4. Castor Beans. 

IV. Animal Preparations. 

1. Cantharides. 

2. Ptomaines. 



SOME COMMON POISONS 263 

0. Neurotics. 

I. Cerebral. 

1. Opium and Kindred Drugs. 

2. Anesthetics, etc. 

II. Spinal. 

1. Strychnine and Kindred Drugs. 

III. Cerebrospinal. 

1. Belladonna and Kindred Drugs. 

3. Individual Susceptibility. — -The effects of any poi- 
son vary greatly with the individual, so that what is 
a toxic dose for one will not even produce serious effects 
upon another. It is impossible, therefore, to make any 
absolute statement as to quantities. For example, the 
usual medical dose of strychnine is probably about % 
of a grain ; yet half that amount has been known to pro- 
duce serious poisoning, while on the other hand two or 
three grains have been taken without fatal results. So 
it is with all poisons. 

4. The Strong Acids. — 

Symptoms. — The three strong acids produce symptoms 
closely resembling, although the hydrochloric is not so 
severe in its effects as the sulphuric and nitric. They 
produce intense burning pain in the mouth, throat, and 
stomach. Vomiting usually follows, the stomach con- 
tents containing, in the case of sulphuric acid, especially, 
shreds of the mucous lining, blood clots, with the whole 
brown to black. With nitric acid the vomited portions 
are yellow to brown. Any spots upon the clothing 
should be observed. Nitric acid makes a brown stain 
not removable by any alkali: hydrochloric is a rather 
bright red turning deeper in color when dry, while sul- 
phuric acid is a deep red, remaining moist and very 
shortly destroying the fabric entirely with a soft sticky 
feeling. 



264 CHEMISTRY FOR NURSES 

Treatment. — The chemical antidote of any acid is an 
alkali or base. Internally, however, or upon the skin, 
only the mildest forms can be used. Upon the clothing 
it is different. Soda is an alkaline salt, readily decom- 
posed by any acid, and an excellent antidote. Like- 
wise, magnesia, a basic oxide, prepared chalk or mag- 
nesium carbonate are all good. But in severe cases of 
any of these acids there is little chance of doing any- 
thing more than to alleviate the sufferings somewhat. 
The stomach pump can not be used as the walls of the 
esophagus and stomach have been so softened as to be 
liable to puncture by the slightest pressure. 

5. Tbe Alkalies.— 

Caustic Soda and Caustic Potash are alike in their 
effects and may be considered together. The mouth and 
throat as well as stomach are severely burned, resulting 
in great pain as was the case with the acids. There is 
a strong, acrid, soapy taste in the mouth and vomited 
portions are apt to be brown in color, occasionally with 
some blood. 

Treatment of Alkali Poisoning. — The antidote is nat- 
urally an acid. The best in such cases are such acids 
as citric, given in lemonade or by grape fruit, and di- 
lute vinegar, if lemons are not to be had. Vegetable 
oils which tend to form emulsions and soaps with the 
alkalies are also helpful, but in severe cases little hope 
can be held out for anything more than temporary re- 
lief. Barley water, very thin gruels and similar sooth- 
ing liquids are also sometimes helpful. The stomach 
pump can not be used for reasons mentioned under the 
acids. 

Ammonia. — Poisoning by ammonium hydroxide is 
rare ; when such happens the symptoms are someAvhat 



SOME COMMON POISONS 265 

more violent and in addition to the caustic effects upon 
the mouth and throat the bronchial tubes and lungs will 
also be seriously irritated. Most ammonia cases are 
those of accident caused by the bursting of pipes in re- 
frigerating plants. In such cases the effects are mostly 
upon bronchi and lungs. Treatment in such cases is 
most difficult and little can be done for relief. 
6. Nonmetallic Elements. — 

Phosphorus. — As has been seen elsewhere it is the yel- 
low variety of phosphorus that is poisonous. Formerly 
children were often poisoned by putting match heads 
into their mouths, but under the present laws this can 
not occur. Some rat poisons contain the yellow vari- 
ety and accidents may occur from that source. Chronic 
cases come in the form of "phossy jaw" from working 
in the factories, but with the safeguards now thrown 
around the industry from beginning to end these should 
be very few in the future. 

Symptoms. — Phosphorus, being an irritant, produces 
violent pain in the throat and stomach, as do the acids 
and alkalies, but usually much slower in appearing. Vom- 
iting usually follows, with considerable thirst. The 
portions thrown up have the characteristic odor of 
phosphorus and will glow in the dark. If death does 
not follow shortly, the nervous system is affected which 
becomes noticeable in twitchings and great prostration. 

Treatment. — There is no satisfactory antidote for 
phosphorus. Emetics should be given, also some mild 
cathartic. As phosphorus is soluble in vegetable or an- 
imal oils, these should not be given as has been sug- 
gested in the case of the alkalies. These oils would 
simply aid in the absorption of the phosphorus into 
the system. 



266 CHEMISTRY FOR NURSES 

Chlorine. — Chlorine, being a gas, attacks the nasal 
passages, bronchi, and lungs. With any very consider- 
able exposure to it the results are very severe. Inflam- 
mation and congestion follow which, except with the 
greatest care, are very apt to be followed by pneumonia 
or other similar troubles. All such cases are very dif- 
ficult of treatment. Ammonia is an antidote for chlo- 
rine, but if used it must be very greatly diluted with 
air. Even then it tends to form an ammonium salt 
within the air passages which in itself is an irritant. 
The fumes of alcohol also will sometimes give slight 
relief. 

Bromine. — This is a heavy, red, very volatile liquid. 
If the fumes are inhaled the results are similar to those 
of chlorine, probably as serious and as difficult to treat. 
More often, however, poisoning by bromine is external, 
in the form of severe burns. Upon the skin it is a pow- 
erful irritant and exceedingly rapid in its action. "Within 
a minute the skin is wrinkled as though it had been in 
hot water for hours ; inflammation and excessive burn- 
ing pain follows. Such wounds should be thoroughly 
washed, then treated with a very mild alkali, such as a 
dilute solution of soda or something similar, then after 
a short time again washed well and a dressing of oil 
applied. Such wounds are slow in healing. 

Iodine. — Although iodine is a commonly used med- 
icine, cases of poisoning by means of it are probably 
rare. Externally it produces irritation, but not suffi- 
cient to call it toxic and no treatment is needed. In- 
ternally it is a violent irritant producing symptoms 
much like the other poisons of this group. Dizziness 
and faintness are sometimes pronounced. Vomited por- 
tions, if starchy foods are present, are apt to be blue, 
or so very dark in color as to appear black. Dilution 



SOME COMMON POISONS 267 

of such portions will show the blue color. Iodine, be- 
longing to the acidic elements, would naturally call for 
an alkaline antidote; hence soda, magnesia, or -some- 
thing similar in small quantities is suggested. Starchy 
foods are also sometimes given, followed by an emetic. 

7. Metallic Compounds. — 

Arsenic Trioxide' and Other Arsenic Compounds. — 
Poisoning by means of arsenic compounds is probably 
by far the most common. It is very difficult to give 
clear-cut, specific symptoms for arsenic poisoning as 
they vary so greatly with different individuals. Per- 
haps the most pronounced is that of severe cramping in 
the calves of the legs accompanied by acute pain in the 
stomach region. Usually this latter is greatly increased 
by pressure. There is usually bad taste in the mouth, 
more or less salivation, and the common irritation of 
throat and esophagus. 

Tests for Arsenic and Treatment. — The tests for ar- 
senic are varied and not difficult to make, as has been 
shown elsewhere. Marsh's test requires time for the 
separation of the arsenic compounds from the food par- 
ticles hence is more often used in postmortem examina- 
tions for legal cases. Reinsch's test is rapid as are sev- 
eral others and requires no special apparatus. As a rule 
arsenic is not a rapid poison and if suspected, tests can 
be made upon any portions of the stomach contents 
thrown up. The antidote has been suggested in 'the 
chapter on arsenic, the best being freshly prepared fer- 
ric hydroxide. The chemicals needed for preparing 
this, ammonia water and ferric chloride, are found in 
every laboratory and pharmacy. 

Antimony. — Poisoning by antimony is most apt to be 
from tartar emetic. The more common symptoms are 
excessive vomiting, purging, great thirst, with a pecu- 



268 CHEMISTRY FOR NURSES 

liar metallic taste in the mouth and severe pains in the 
throat and stomach. Tannic acid is said to be the best 
antidote, after the use of which the stomach pump 
should be used and plenty of water. 

Mercury. — Poisoning by mercury salts is somewhat 
common. Salivation from use of calomel is not nearly 
as frequent as some years ago when precautions now 
used were not taken. But corrosive sublimate tablets 
are often mistaken for harmless ones ; moreover, there 
is a widespread idea that death by mercuric chloride 
poisoning is painless, hence it has frequently been used 
by suicides in late years. The usual symptoms of se- 
vere pain in the stomach follow rapidly upon swallow- 
ing the drug; respiration becomes painful and not deep; 
pulse weak and irregular; great thirst; severe cramping 
in arms and legs; abdomen becomes swollen and very 
sensitive to pressure ; continued metallic taste in the 
mouth and if death does not come for some days, the 
usual effects of mercury upon the salivary glands and 
teeth. 

Treatment for Mercury Poisoning. — The best antidote 
is the white of eggs. This forms an insoluble compound 
with the mercury and prevents its absorption by the 
system. It is said, however, that like many other cases 
as for example, mercuric iodide in excess of potassium 
iodide, mercury salts are soluble in excess of albumin; 
the precaution must be taken, therefore, not to overdo 
the treatment by giving too much of the white of eggs. 
One egg is sufficient for four grains of the corrosive 
sublimate. If eggs are not at hand milk will do but 
not so well. 

Lead Poisoning. — As has been suggested elsewhere, 
lead poisoning is usually of chronic form, that is, it 
comes through the gradual accumulation of lead salts 



SOME COMMON POISONS 269 

ill the system. This is more often found with the work- 
men in the white lead factories or with painters who 
absorb it through the pores of the skin: often it comes 
from use of cosmetics and hair tonics. It produces 
what is known as painters' or lead colic. It may result, 
however, from drinking water, which enters through 
service pipes of lead, very unusual at the present time, 
or from external applications in case of ivy poisoning 
or other skin troubles. The symptoms appear very 
gradually: loss of appetite, general debility, metallic 
taste persistent in the mouth, indigestion, and unusual 
thirst. Constipation usually accompanies, with move- 
ments very dark when they do occur. Often, perhaps 
usually, a bluish line appears along the front teeth es- 
pecially where they meet the gums. Later the muscles 
of the arm become more or less palsied for which rea- 
son the disease is sometimes spoken of as lead palsy. 

Triatnitnt for Lo:id Po ; s<n>- : < .</ . — There is no good an- 
tidote for lead poisons. It is perhaps most insoluble in 
the form of a sulphate, hence the giving of some sol- 
uble sulphate like magnesium sulphate would be ex- 
pected. Sodium sulphate might also be used, but the 
Epsom salt serves as a purgative at the same time ren- 
dering the lead insoluble, hence it is the better. How- 
ever, as the lead is throughout the system and not 
simply in the digestive tract alone, no antidote can 
give immediate or even any relief except in small degree. 
The conditions causing the trouble must be removed 
and there is then some possibility that the individual 
may eventually throw oft the poison. 

Copper Poisoning. — Poisoning by copper salts more 
often comes through food products. Housewives some- 
times prepare their green pickles by adding small 
amounts of blue vitriol or bv heating for a time the 



270 CHEMISTRY FOR NURSES 

vinegar and vegetable to be prepared in a brass kettle. 
Either method gives a beautiful natural green color to 
the finished product; until the pure food laws became 
severe such addition of copper salt was not uncommon 
in the pickles found in the grocery. Apple butter is 
sometimes innocently prepared in large brass kettles 
or boilers with copper bottoms: in either case a consid- 
erable amount of copper salt finds its way into the food 
product. Probably, only with individuals specially sus- 
ceptible to copper poisoning would the amount con- 
tained be sufficient to produce serious results, but they 
sometimes follow use of such food products. The symp- 
toms are similar to those of lead, but the line at the teeth 
will be of a greenish color. 

Antidote for Copper. — The most insoluble compound 
of copper obtainable under such circumstances is the 
ferrocyanate. This may be prepared in the laboratory 
by adding potassium ferrocyanate solution to a copper 
salt. If the ferrocyanate is given in dilute solution to 
the patient, the insoluble compound is obtained; this 
must be removed by emetics. If this antidote is not 
accessible, white of eggs or milk will also serve the 
purpose. 

Zinc Salts. — Several zinc compounds are used more 
or less in medicine. The chloride constitutes the main 
ingredient of a certain cancer remedy; zinc oxide is 
used in various skin applications ; zinc sulphate is some- 
times given as an emetic. As the last closely resembles 
Epsom salts in its appearance, it has sometimes been 
taken in that way by mistake. All of the uses suggested 
permit of accidental poisoning by them. Taken inter- 
nally, especially in large doses, all zinc compounds are 
violent irritants and cause intense pain, vomiting and 
purging. Perhaps as good treatment as can be sug- 



SOME COMMON POISONS 271 

gested is the albumin of eggs, or milk, or common soda 
dissolved in water. All should be followed by emetics 
or the use of the pump and evacuation of the intestinal 
tract. 

8. Vegetable Compounds. — 

Oxalic Acid. — Oxalic acid is found in nature in rhu- 
barb and various other plants. It is manufactured from 
sawdust or sugar by treating them with strong nitric 
acid. On account of its cheapness and ease of obtain- 
ing, it is often used for suicidal purposes. Symptoms 
of oxalic poisoning are so varied it is difficult to give 
any description. In concentrated form it causes pro- 
nounced twitching of the muscles of the extremities, 
prostration and heart depression. Later cramps, deli- 
rium and even convulsions may follow. 

Antidote for Oxalic Acid. — From its nature the anti- 
dote would be alkaline in character; hence, magnesia 
or milk of lime, especially the latter as it would form 
the oxalate of calcium, the most insoluble of the com- 
pounds. Prepared chalk is also good as it gives the 
same reaction. Soda, usually a good antidote for acids, 
would not do here for sodium oxalate the product re- 
sulting is poisonous and soluble and hence would pass 
into the system as readily as oxalic acid itself. The 
usual methods of following by an emetic or use of the 
stomach pump should be observed. 

Phenol. — This compound is perhaps more often sold 
under the name of Carbolic Acid, though, strictly speak- 
ing, it is more properly an alcohol, as the ending indi- 
cates. It is widely used in medicine both as an anti- 
septic and deodorant and frequently is the cause of 
accidental or premeditated death. Applied externally 
it blisters the skin and turns it white, producing local 
anesthesia. Internally it causes intense burning pains; 



272 CHEMISTRY FOR NURSES 

the temperature is lowered, likewise the respiration; 
pulse weak, but rapid; delirium, convulsions or coma 
and death. 

Treatment for Phenol. — Owing to the muscles of the 
stomach being more or less completely anesthetized, emet- 
ics will not cause the removal of the stomach contents in 
cases of poisoning by carbolic acid. Sodium sulphate is 
recommended as the best antidote, given in a cup of water, 
Milk of lime or soap suds may also be used. In any case 
the stomach pump should follow. 

Croton Oil. — This is perhaps the most powerful purga- 
tive used in medical science. It is a violent poison; one 
of the first symptoms which follow rapidly the taking 
of the oil is intense pain in the stomach, griping, vom- 
iting and purging. These follow one another at fre- 
quent intervals, accompanied by great pain, ending with 
convulsions, collapse and death. Successful treatment 
is very difficult, Probably olive oil, followed by soap 
suds and the stomach pump is as effectual a method as 
any. 

9. Animal Products. — 

Cantharides. — This is often known as Spanish Fly. 
It is a small beetle found in Spain in abundance, con- 
taining an active principle known as cantharidin. 
Ground cantharides is a brown powder, containing bright 
green particles, and having a disagreeable odor. It is 
used in plasters to produce blisters. It is a violent poi- 
son and taken internally, causes intense suffering, vom- 
iting and purging, great thirst and difficulty in swal- 
lowing. The urinary and genital organs especially 
are irritated. The only treatment is by an emetic or 
evacuation of the stomach as speedily as possible. 

Ptomaines. — This class of poisons in the outline has 
been placed under "Animal Products. " Ptomaines are 



SOME COMMON POISONS 273 

really chemical compounds belonging to what are called 
amines or substituted ammonias. Thus, NH 3 is ammo- 
nia; it is possible to remove one or more of the hydro- 
gens and substitute therefor hydrocarbon groups. Thus, 
the group, CH 3 , methyl, may be substituted for one of 
the hydrogens in ammonia giving the compound, 
NH 2 CH 3 , called methyl amine. The ptomaines belong 
to this class of compounds. They are the result usually 
of the decomposition of meat or meat products, as all 
such food products contain nitrogen in addition to the 
hydrogen and carbon necessary for the formation of the 
amines. Symptoms vary to such an extent that no 
general statement can be given. Furthermore no anti- 
dote can be offered and each case must be taken on its 
individual peculiarities. 

10. The Neurotics. — From the nature of the drugs be- 
longing under this heading and from the stringency of the 
laws regarding the sale of such drugs it probably would 
not be of value to discuss them in a work of this size. 
In the table which will be found on page 276 in the 
next chapter some of their more general symptoms and 
method of treatment will be given. This will probably 
be sufficient for the student's needs. 

Exercises for Review 

1. Give the three main divisions of the poisons. 

2. Into what two classes are the irritants proper divided? Give 
three examples under each division. 

3. What are the more striking symptoms in case of the strong 
acids? 

4. What is the antidote for an acid? Why? What is the 
chemical action? 

5. Are chalk and soda alkalies? Why may they be used as 
antidotes for acids? 

6. What is the natural antidote for an alkali? Why? What 
particular acid would you suggest? 



274 CHEMISTRY FOR NURSES 

7. Would hydrochloric acid do as an antidote for caustic soda 
poisoning? Give reason for your answer. 

8. What may be the sources of phosphorus poisoning? 

9. Give two methods which would render sure your diagnosis 
of phosphorus poisoning? 

10. What is the recommended treatment for such cases? 

11. Why are chlorine and ammonia specially difficult of treat- 
ment? What is suggested in each case? 

12. Wherein lies the chief danger in chlorine poisoning in case 
death is not prompt? 

13. What cases of bromine poisoning are most apt to be met 
with? What is the treatment? 

14. What is one of the principal things to observe as aid to 
diagnosis in iodine poisoning? 

15. Give two tests for arsenic. Which is the delicate one? 

16. What two antidotes are suggested for arsenic? How is 
the first made? 

17. What are the two commoner sources of poisoning by mer- 
cury ? 

18. What are some of the more pronounced symptoms in mer- 
curial poisoning? 

19. What is the treatment for bichloride of mercury poisoning? 
Why is albumin suggested in many cases? 

20. What kind of a poison is lead? What disease does it 
cause? What are some of the symptoms? 

21. What is the treatment for lead palsy? Why can it not 
have immediate or pronounced results? 

22. How may copper poisoning come through food products? 

23. Why does the housewife sometimes prepare such products 
in brass kettles? 

24. What is the treatment for both zinc and copper poisoning? 

25. What is the antidote for oxalic acid? Why not soda as 
was suggested for other acids? 

26. What is phenol? Give its external effects. 

27. Why are emetics of little avail in carbolic acid poisoning? 

28. What antidotes are suggested for phenol? 

29. What is the use of Cantharides? What is its internal 
effect? 

30. What are ptomaines? How produced? What can be said 
of treatment? 



APPENDIX 



Table of More Common Poisoxs — Diagnosis — Antidotes 



NAMES 


AID IX DIAGNO- 
SIS 


SYMPTOMS 


AXTIDOTE OR TREAT- 
MENT 


Sulphuric 

acid — Oil of 

Vitriol 


On clothing, 
red spot, re- 
mains moist, 
sticky, hole 
appears. 

Brown spots 
on clothing or 
skin. Xot re- 
moved by al- 
kali. 

Bright red 
sj)ots on cloth- 
i n g ; turn 
deeper red. 
Dry. 


Intense pain, 
vomit black or 
bloody shreds of 
mucous lining. 


Soda, milk of 
lime, chalk, barley 
water. Xo pump. 


Xitric acid 
Aqua fortis 


Same as above ■ 
vomit yellow or 
brown. 


Same as above. 


Hydrochloric 
Muriatic 


Same as above : 
less severe. 


Same as above. 


Sodium and 
Potassium 
Hydroxides 


Make skin 
slippery; 

woolen cloth 
likewise. 


Severe burning 
pain ; acrid soapy 
taste. 


Lemonade, grape 
fruit juice, diluted 
vinegar. Xo pump. 


Ammonia 


Odor of 
breath. 


Burning pain 
bronchi and lungs. 


Very dilute 
chlorine from 
bleaching* powder. 


Phosphorus 


Odor of 
breath. Glow 
in dark of 
vomit. 


Slower violent 
pain, thirst, nerv- 
ous symptoms. 


Emetics and mild 
cathartics: no veg- 
etable oils. 


Chlorine 


Odor of 
breath. 


Catarrhal effects, 
burning bronchi 
and lungs. 

Serious burns on 
skin, intense pain. 

Severe pains, 
dizziness, faint- 
ness. 


Very dilute am- 
monia, alcohol 

fumes. 


Bromine 


Shriv e 1 e d 
skin, brown 
stain. 


Mild alkalies, 
sod a, limewater, 
oils. 


Iodine 


Stain, odor. 
Vomit blue. 


Mild alkalies, 
emetics. 


Arsenic 
trioxide, 
Arsenic 


Rein sell's 
test. 


Crampi o g i;i 
calves of legs, pain 
in abdomen, great- 
er by pressure. 


Ferric hydroxide, 
freshly made, mag- 
nesia. 



275 



276 



CHEMISTRY FOR NURSES 



Table of More Common Poisons — Diagnosis — Antidotes — Cont'd 



NAMES 


AID IN DIAGNO- 
SIS 


SYMPTOMS 


ANTIDOTE OR TREAT- 
MENT 


Antimony 

tartrate ; 

tartar 

emetic 




Metallic taste, 
purging, vomiting 
excessive. 


Tannic acid, 
pump, water. 


Mercury 
bichloride, 
Corrosive 
sublimate 


Rein sch's 
test. See text. 


Breathing shal- 
low, weak, pain- 
ful, pulse weak, 
cramps in arms 
and legs. 


Egg albumin, 
milk. 


Lead salts 


Blue line on 
gums, general 
debility. 


Metallic taste 
persistent, no ap- 
petite, indigestion, 
constipation, palsy 
in arms. 


Magnesium sul- 
phate. Recovery 
slow. 


Copper salts 


Green line 
on gums. 


Much like lead. 


Potassium ferro- 
cyanate ; egg al- 
bumin, milk. 


Zinc salts 




Violent pain, 
purging. 


Egg albumin, 
milk. 


Oxalic acid 




Twitching o f 
muscles, prostra- 
tion, cramping. 


Chalk, milk of 
lime, pump. 


Phenol, 

Carbolic 

acid 


B 1 i s tered 
skin. 


Intense burning 
pain, lowered tem- 
perature, weak 
pulse, rapid. 


Sodium sulphate, 
milk of lime, soap 
suds, pump. No 
emetics. 


Croton 
oil 


Violent purging, 
frequent, griping 
pains. 


Olive oil, soap 
suds. 


Cantharides 


Green wing 
portions. 


\ iolent vomit- 
ing, purging, uri- 
nary organs in- 
flamed. 


Emetic. 


Morphine 

and 

Opium 




Narcotic. 
Drowsiness, stupor, 
coma. Breathing 
slow, stertorous. 


Strong coffee, 
atropine, stomach 
washed by< pu'mp. 
Keep awake if 
possible. 


Chloral, 
Chloral 
hydrate 




Sleep quiet ; in 
large doses, pulse 
weak, sleep heavy, 
coma. 


Keep body 
warm ; artificial 
respiration, heart 
stimulants. 



APPENDIX 



277 



Table of More Covtmox Poisons — Diagnosis — Antidotes — Cont'd 



NAMES 


AID IX DIAGNO- 
SIS 


SYMPTOMS 


ANTIDOTE OR TREAT- 
MENT 


Strychnine, 

Xux vomica, 

Brucine 




Rest lessness, 
twitching, difficulty 
in breathing, tetan- 
ic convulsions, face 
ghastly. 


Strong tea, tan- 
nin, followed by 
pump ; potassium 
bromide, chloro- 
form to prevent 
convulsions. 


Belladonna, 
Atropine 




Dryness of mouth 
and throat, nausea, 
dizziness, poor vi- 
sion, pulse rapid, 
face flushed. 


Tannic acid, 
evacuation by 
pump, cathartics. 


Cocaine 




X e r v o usness, 
fullness of head, 
nausea, poor vision, 
rapid, feeble pulse, 
breathing shallow. 

Breathing diffi- 
cult, pulse slow, 
paralysis, death. 




Prussic acid 

Hydrocyanic 

acid 




Action too rapid 
in toxic doses for 
treatment. 



The Periodic Law 

The student may have wondered in some cases why 
certain elements have been grouped as they have been 
in a particular family, when there is marked difference 
in the characteristics. In the case of the chlorine fam- 
ily, or the sodium family, so far as we have seen there 
is a marked resemblance among them all; but in other 
cases as in the carbon family, there is not much simi- 
larity in many respects. 

As long ago as the middle of the preceding century 
a number of chemists held a belief that all the elements 
bore some multiple relation to hydrogen; moreover, 
they had observed that elements similar in properties 
were separated from each other in atomic weight by 
certain definite amount. But it was not until about 
1870 that Mencleleeff, a noted Russian chemist, greatly 



278 CHEMISTRY FOR NURSES 

extended these conceptions and perfected them. He 
observed that on arranging the elements in accordance 
with theif atomic weights, those with similar properties 
seemed to recur at regular intervals. Thus, Li, Gl, B. 
C, N, 0, F, Na, Mg, Al, Si, P, S, CI, K, Ca, Sc, Ti, etc., 
are arranged in accordance with their increasing atomic 
weights. Beginning with lithium the first element which 
is like it in properties is sodium, the eighth one; and 
the next after that which is like these two is potassium, 
another octave beyond. If we take fluorine, and count 
on from that we come to chlorine, with similar prop- 
erties, the eighth beyond. Allowing for undiscovered 
elements at the time Mendeleeff was working upon this 
arrangement he came to the conclusion that the ele- 
ments may be arranged in families depending solelv 
upon their atomic weights. In other words he con- 
cluded that the properties of an element depend in some 
way upon the atomic weight of that element. This idea 
has now been accepted by chemists as a whole, and the 
elements have been arranged in a table known as the 
Periodic Table. 

There are a great many very interesting facts which 
may be observed regarding the elements in connection 
with this table, but it is not the purpose to bring them 
out here. By a hasty inspection it will be seen that the 
families as we have studied them are found in the table 
in vertical groups. 



APPENDIX 



279 



Eh 



O 
« 

Ph 



(rasvanxvs iii 
2, = honstva 


as 


o 

00 
L0> 




cm 










(raxvanxvs £i 
9 = sonstva 


<£> CM 

O GG 


CM 

C: 

QQ 

5 


iq 

CM 

H 

cT 

o EH 

6 s 

3 


GO 

rH 




LO 

GO* 

co 
cm 

t3 


aaxvanxvs iii 

g = 30 .KHIVA 


rH rH 

T^ CO 

{Z^PhT 


LO 

> 


CO* 

Oi 

a 


GO 
O 
CM* 

GO 
r-^ 
of 

Eh 






f = sonh^va 


O~o3 




H 

c3 


o 

CM 

a 


CM* 

CO 


g = sonstva 


tH i>- 
rH EM 


o 

c? 

O 
m 


T— 1 

iH 

H 
OS 

GO 


o 
Eh 

Ci 
CO 
rH 

cf 






Z — sonstva 


CO 
CM 

s 


IO 

CO^ 

N 
o 

cf 
Q 


cm 

i— i 

rH 
CO ^ 

00^ 

#2 


O 

o 

rH CM 

t>: bjc 

PQ 


CO* 

cm 

P3 


X = sonstva 


CO 

J!3 


CO 

CO 

a 

as 

CO 


00 

o 

rH 

LO* 

00 

05 


b- 

Oi 

CO S 

CO 

rH 

m 

o 






SdNflOJJSrOO ox 

= sonstva 




CO • 


CO '. 
00^ . 

M : 


O 
CO 
rH^ 




-4- 


) 
1 

] 
I 
r 



W3 <JJ * 

o c5 bo 

I 3 1 

O G 

O— rt 

o.j: g 1 

c y.rJ 
o&g 

a ^ 
"S <^ .„ 

£*o^ 

en aj 

^'S2 



Is" --2 

"1st 

en ""■ 

"« JJ JJ £ 
a; rt *g^ 
+3 cu ^ V 



III 2 

? £ §§ 

o 

12 S 



280 



CHEMISTRY FOR NURSES 



Solubilities of Common Compounds 

It may be desirable to know at times whether a com- 
pound is soluble in water. A few general rules may be 
helpful and are given below. 

(a) All salts of the sodium group, including those of 
ammonium, are soluble, with the exception of two or 
three very uncommon ones. 

(b) All bromides are soluble except those of lead, 
mercury, and silver. 

(c) All carbonates of the sodium group, including 
ammonium, are soluble ; all others are insoluble. 

(d) All chlorates are soluble. 

(e) All chlorides are soluble except lead chloride, mer- 
curous chloride, and silver chloride. 

(f) The hydroxides of the sodium group, ammonium, 
and the calcium group are soluble, calcium only moder- 
ately so, while all others are insoluble. 

(g) All nitrates are soluble. 

(h) The oxides of the sodium and calcium group are 
chemically soluble in water, that is, they react to form 
a new compound, the hydroxide. All other oxides are 
insoluble in water. 

(i) Phosphates are insoluble except those of the al- 
kali metals and ammonium. 

(j) Silicates are insoluble except those of the alka- 
lies and ammonium. Even then if mixed with silicates 
of heavier metals they are insoluble. 

(k) The sulphates of barium, calcium, lead, and stron- 
tium are insoluble; others are soluble. 






APPENDIX 



281 



Some Interesting Temperatures 



Absolute zero 


-273° C 


Hydrogen melts 


-260 


Hydrogen boils 


-252.0 


Nitrogen melts 


-214 


Nitrogen boils 


-194 


Oxygen boils 


-182.5 


Alcohol freezes 


-130 


Mercury freezes 


- 39.5 


Water freezes 





Room temperature 


21 


Ether boils 


34.6 


Human body 


37 


Wood's Metal melts 


60 


Alcohol boils 


78.5 


Water boils 


100 


Sulphur melts (rhomb) 


114.5 


Tin melts 


232 


Lead melts 


327 


Murcurv boils 


357 


Zinc melts 


419 


Dull red heat 


650 


Aluminum melts 


660 


Bright red heat 


1,000 


Gold melts 


1,064 


White heat 


1,350 


Iron melts 


1,520 


Platinum melts 


1.750 


Corundum melts 


2,000 (about) 


Oxylrydrogen flame 


2.500 


Oxyacetylene flame 


2,700 


Tungsten melts 


3,000 


Thermit gives 


3,500 (about) 


Electric arc 


4,000 (about) 



282 CHEMISTRY FOR NURSES 

Tables of Weights and Measures 

Weights 
10 milligrams ('mg.) — 1 centigram (eg.) 
10 centigrams —1 decigram (dg.) 

10 decigrams — 1 gram (g.) 

1,000 grams — 1 kilogram (kg.) 

English Equivalents 
1 kilogram — 2.2046 pounds 

28.35 grams = 1 ounce 

1 gram =15.43 grains 

500 grams = 1.1023 pounds 

The unit of weight in the Metric System is the gram. 

Volumes 
1,000 cubic centimeters (c.c.) =1 liter 
1 cubic decimeter (c.d.) =1 liter 
1 liter (1.) =1.056 liquid quarts 

The unit in the Metric System is the liter. 

Length 
10 millimeters (mm.)— 1 centimeter (cm.) 
10 centimeters — 1 decimeter (dm.) 

10 decimeters =1 meter (m.) 

English Equivalents 
1 centimeter — 0.3937 inches 

2.54 centimeters r= 1.0 inch 

1 meter ~ 39.37 inches 

Thermometer Equivalents 
For scientific work the centigrade thermometer is always used 
and readings given in scientific books are always centigrade unless 
otherwise specified. Freezing water is 0° C. and boiling point is 
100° C. 

Centigrade is 32 Fahrenheit and 273 Absolute 
100 " "212 " "373 " 

One degree Centigrade = % of a degree Fahrenheit 
One degree Fahrenheit =:% of a degree Centigrade 
One degree Centigrade —. One degree Absolute 

To convert centigrade degrees into Fahrenheit, multiply by % 
and add 32, algebraically. This means that if the centigrade read- 
ing is below zero, it would have the minus sign and one would be 



APPENDIX 



283 



subtracted from the other. To convert Fahrenheit readings into 
centigrade multiply by % after subtracting 32 from the Fahrenheit 
reading. 

List of Elements, Their Symbols and Atomic Weights. (0=16.) 
(The more important elements are printed in heavy type.) 



NAME OF 
ELEMENT 



Aluminum . 
Antimony . 

Argon 

Arsenic . . . 
Barium .... 
Bismuth . . . 

Boron 

Bromine . . . 
Cadmium . . 
Caesium . . . 
Calcium . . . 
Carbon 
Cerium 
Chlorine . . . 
Chromium . . 

Cobalt 

Columbium 

Copper 

Dysprosium 
Erbium . . . 
Europium . 
Fluorine . . . 
Gadolinium 
Gallium . . . 
Germanium 
Glucinum . . 

Gold 

Helium 
Holmium . . 
Hydrogen . . 
Indium 
Iodine .... 
Iridium . . . 

Iron 

Krypton . . 
Lanthanum 

Lead 

Lithium . . . 
Lutecium . . 
Magnesium 
Manganese 
Mercury . . . 



SYM- 
BOL 



Al 

Sb 

A 

As 

Ba 

Bi 

B 

Br 

Cd 

Cs 

Ca 

C 

Ce 

CI 

Cr 

Co 

Cb 

Cu 

Dy 

Er 

Eu 

F 

Gd 

Ga 

Ge 

Gl 

Au 

He 

Ho 

H 

In 

I 

Ir 

Fe 

Kr 

La 

Pb 

Li 

Lu 

Mg 

Mn 

Hg 



ATOMIC 
WEIGHT 



27.1 

120.2 
39.88 
71.96 

137.37 

208.0 
11.0 
79.92 

112.4 

132.81 
40.07 
12.00 

140.25 
35.46 
52.0 
58.97 
93.5 
63.57 

162.5 

167.7 

152.0 
19,0 

157.3 

69.9 

72.5 

9.1 

197.2 
3.99 

163.5 
1.008 

114.8 

126.92 

193.1 
55.84 
82.92 

139.0 

207.1 
6.94 

174.0 
24.32 
54.93 

200.6 



XAME OF 
ELEMENT 



Molybdenum . , 
Neodymium . . 

Neon 

Nickel 

Niton 

Nitrogen 

Osmium 

Oxygen , 

Palladium . . . 
Phosphorus . . 
Platinum .... 
Potassium . . . 
Praseodymium 

Radium 

Rhodium 

Rubidium .... 
Ruthenium . . . 
Samarium . . . 
Scandium 
Selenium .... 

Silicon 

Silver 

Sodium 

Strontium 

Sulphur 

Tantalum 
Tellurium .... 

Terbium 

Thallium .... 

Thorium 

Thulium 

Tin 

Titanium .... 

Tungsten 

Uranium 
Vanadium . . . 

Xenon , 

Ytterbium . . . 

Yttrium 

Zinc 

Zirconium . . . 



SYM- 
BOL 



Mo 

Nd 

Ne 

Ni 

Nt 

N 

Os 

O 

Pd 

P 

Pt 

K 

Pr 

Ra 

Rh 

Rb 

Ru 

Sa 

Ss 

Se 

Si 

Ag 

Na 

Sr 

S 

Ta 

Te 

Tb 

Tl 

Th 

Tm 

Sn 

Ti 

W 

U 

V 

Xe 

Yb 

Yt 

Zn 

Zr 



ATOMIC 
WEIGHT 



96.0 

144.3 

20.2 

58.68 

222.4 

14.01 

190.9 

16.00 
106.7 
31.04 
195.2 
39.1 
140.6 
226.4 
102.9 

85.45 
101.7 
150.4 
44.1 
79.2 
28.3 
107.88 
23.00 
87.63 
32.07 
181.5 
127.5 
159.2 
204.0 
232.4 
168.5 
119.0 
48.1 
184.0 
238.5 
51.0 
130.2 
172.0 
89.0 
65.37 
90.6 



4 y 



284 CHEMISTRY FOR NURSES 



Names and Formulas of the More Common Chemicals 

Acetic acid ' HC o H 3 2 

Alcohol C 2 H 5 OH 

Alum, ammonium (NH 4 ) 2 Al o (SOJ^ 

Alum, potassium K Al (SO ) 

1 x 2 2 4 4 

Aluminum oxide ^2^1 

Aluminum sulphate Al ( SO ) 3 

Ammonium bicarbonate NH HCO 

carbonate '. (NH 4 ) 2 C0 3 

chloride NH 4 C1 

' < hydroxide NH 4 OH 

nitrate NH 4 NO g 

sulphate (NH 4 ) 2 S0 4 

Antimony oxy chloride SbOCl 

trichloride SbCl 3 

' ' trisulphide Sb 2 S s 

Arsenic trioxide ^s 9 O o 

Barium carbonate BaCO^ 

chloride BaCf ' 

i i dioxide BaO o 

hydroxide Ba(OH)., 

" nitrate Ba(NO ) 

oxide BaO 

' ' sulphate BaSO 

Bismuth chloride BiCl 

'■' nitrate Bi(NO.,). 

< ' subnitrate BiONO 

' ' trioxide Bi O 

Bleaching powder CaCl(OCl) 

Borax Na B O 

2 4 7 

Calcium carbide CaU 

' ' carbonate CaCO, 

11 chloride CaClJ* 

' ' fluoride CaF * 

" hydroxide Ca(OH) o 

' ' oxide (lime) CaO 

6 ' phosphate Ca (PO ) 

1 ' sulphate CaSO^ 

Carbolic acid C H_OH 

Carbon disulphide , CS 



APPENDIX 285 

Chloroform CHCl o 

Chrome vellow PbCrO 

4 

Cinnabar HgS 

Copper acetate Cu(C H 9 ) o 

chloride CuCl* 

" nitrate Gu(XOJ o 

1 ' oxide CuO 

' < sulphate CuSO 

" sulphide CuS 

Ether, sulphuric (C ,H e ) O 

Ferric chloride Fe^Cl^ 

' ' hydroxide Fe~ (OH) 

" nitrate Fe 2 (NO ) 

" oxide Fe O 

2 < 

Ferrous sulphate FeSO 

4 

Ferrous sulphide FeS 

Fluor spar CaF f> 

Gold trichloride AuCl 

3 

Hydrochloric acid HC1 

Hydrofluoric acid HF 

Hydrogen peroxide ^- 9 0<> 

Hydrogen sulphide H q S 

Hypo-chlorous acid HCIO 

Iodic acid HIO. 

Iodoform CHI^ 

Lead acetate Pb(C o H,OJ. 

1 ' carbonate PbCO~ 

' ' chloride PbC\" 

' ' chromate PbCrO 

" nitrate Pb(N0 4 ) 9 

" oxide (litharge) . ... PbO 

' ' sulphate PbS0 4 

Lime CaO 

Litharge PbO 

Lithium chloride LiCl 

Magnesia MgO 

Magnesium carbonate MgCO. 

chloride MgClj 1 

' ' oxide MgO 

sulphate MgS0 4 

Manganese dioxide .MnO 

° 2 



286 CHEMISTRY FOR NURSES 

Mercuric chloride HgCl 

' ' iodide H ^2 

" nitrate ;Hg(N0 3 ) 2 

oxide H^O 

sulphide HgS 

Mercurous chloride Hg CI 

& 2 2 

' ' iodide Hg 9 I 

" nitrate HgJ(NO ) o 

Minium , Pb O 

3 4 

Phosphine PH o 

Phosphorus pentoxide P O r 

Plaster of Paris Ca 2 S0 4 , H 2 

Platinum tetrachloride ^Cl^ 

Potassium acetate KC 2 H^0 2 

bicarbonate KHCO 

bromide KBr 

carbonate K r CO r ^ 

chlorate KCIO* 

chloride KC1 

chromate K CrO 

° 4 

cyanide KCy 

dichromate K Cr O 

2 2 7 

ferricyanide K i? Fe(CN) 

ferrocyani.de K Fe(CN) 

hydroxide KOH 

iodide KI 

nitrate KNO„ 

nitrite KN0 9 

permanganate KMnO 

sulphate K SO 

-L 9 4 

sulphocyanate KSCN 

Silica SiO 

2 

Silver bromide AgBr 

' ' chloride AgCl 

i ' iodide Agl 

i i nitrate . AgNO o 

Sodium acetate NaC H O 

2^2 

' ' arseniate Na AsO 

3 4 

' l arsenite Na o AsO. 

' ' bicarbonate NaHCO 

3 
' l carbonate Na CO 

2 3 



APPENDIX 287 

Sodium chloride NaCI 

hydroxide NaOH 

' i iodide Nal 

' ' nitrate NaNO 

' ' nitrite NaNO 

" phosphate ....NaPO 

1 ' sulphate . ISTa SO 

' t sulphide NTa*S 

sulphite Na 2 o SO o 

' ' thiosulphate Na~S O 

x 2 2 3 

Stannic chloride SnCl 

' < oxide SuO o 4 

Stannous chloride SnCl %> 

Strontium nitrate Sr (NO ) 

Sulphur dioxide SO 

Sulphuric acid H,SO 

Sulphurous acid H q SO 

Sulphur trioxide SO 

Zinc chloride ZnCl^ 

' ' oxide ZnO 

' ' sulphate ZnS0 4 



GLOSSARY 



Chemical Terms 

Actinic. Actinic light rays are those which have the power of 
producing chemical change in substances, as upon a photo- 
graphic plate. 

Alkali. A soluble hydroxide, with caustic properties, sharp bit- 
ing taste, and power of corroding the skin. 

Allotropic. Literally, another form of an element; more often 
applied to the unusual form. Ozone as related to oxygen. 

Alloy. A mixture of two or more metals, melted together so as 
to be homogeneous. Example, brass. 

Amalgam. An alloy, one component of which is mercury. 

Amorphous. Without special form; uncrystallized. 

Anesthetic. A substance used to produce unconsciousness. 

Anhydride. An acidic oxide. An oxide forming an acid on the 
addition of water. 

Anhydrous. Without water. 

Antiseptic. An antiseptic is a substance used to prevent de- 
cay or destroy pathogenic bacteria. 

Basic. Having the properties of a base or alkali. 

Binary. A compound consisting of two elements. 

Calcine. To heat strongly. 

Commercial. A term applied to chemicals not pure but suffi- 
ciently so for all ordinary uses. 

C. P. Chemically pure. Applied to a better grade of chemicals 
than those marked ' ' commercial. ? ' 

Decant. To pour off a liquid from a precipitate. 

Deliquesce. To gather moisture from the air and become liquid. 

Desiccator. A vessel used for drying substances. 

Destructive Distillation. Heating a substance in a closed re- 
tort so as to decompose it and produce new substances; as 
in distilling coal. 

Downward Displacement. Collecting a gas heavier than air by 
letting it flow downward into a bottle full of air, thus dis- 
placing the air. 

Distillate. The liquid obtained by distillation. 

288 



GLOSSARY 289 

Dyad. An element with valence of two. 

Effloresce. To give up water of combination at room temper- 
ature and become a powder. 

Electrode. The terminal of a battery. 

Empirical. Applied to a formula which shows composition only. 
Xot structural. 

Escharotic. A caustic. A substance which corrodes. 

Filtrate. The liquid which passes through a filter. 

Floccuient. Flaky; often applied to certain precipitates. 

Elux. A substance used to lower the melting point of some sub- 
stance: often it is a solvent for the substance. 

Fractional Distillation. Boiling a liquid and separating it into 
portions or fractions by means of their difference in boiling 
points. 

Gelatinous. Jelly-like or starch-like paste; applied to precipi- 
tates. 

Germicide. A substance destructive of germs. 

Gravimetric. Applied to determining the proportion by v: eight. 

Halogens. Literally, salt producers: the chlorine family. 

Hydrated. Containing water. 

Hydroxyl. The group HO, found in all hydroxides. 

Hygroscopic. Having the property of becoming moist in damp 
air. 

Indicator. A substance, like litmus paper, used to determine 
when a reaction has been completed. 

Ion. An electrically charged atom or group of atoms. They 
may be either ijositive. called cations; or negative, called anions. 

Isomeric. Two compounds are isomeric when they have the 
same percentage composition, the same empirical formula, 
but are entirely different in properties. 

Monad. An element with a valence of one. 

Monobasic. Applied to an acid having only one displaceable 
atom of hydrogen in a molecule, as hydrochloric acid. 

Mordant. Something used to set the color or dye in cloth. 

Nascent. Literally, being set free; applied to a gas as it is be- 
ing set free from some compound: in the atomic form and 
very active, chemically. 

Neutral. Neither acid nor alkaline in character. 

Neutralization. The process of combining an acid and a base so 
as to exactly destroy the properties of each and form a new 
compound. 



290 CHEMISTRY FOR NURSES 

Nitrogenous. Containing nitrogen. 

Occlude. To condense within the pores of a metal; as hydrogen 
in platinum or carbon monoxide in hot cast iron. 

Oxidation. The combining of a substance with oxygen. In a 
broader sense, raising the valence of an element. 

Oxidizing Agent. A substance which will bring about oxidation. 
Usually a substance containing oxygen, with which it will 
part readily. Often chlorine or bromine. 

Paste. A very pure form of flint glass used in making imitation 
diamonds. 

Pneumatic. Term applied to the trough used in collecting gases. 

Polymer. A term applied to one compound the multiple of an- 
other. Thus, C ,H is a polymer of C H . 

Precipitate. A solid thrown out in a solution; it may be a 
mere cloud or so very dense and heavy as to settle very 
rapidly. 

Radical. A group of atoms which act chemically as if a single 
element. 

Reaction. The chemical change taking place between two or 
more substances. 

Reagent. A substance used in a chemical reaction. 

Roast. To heat strongly in presence of air; hence to oxidize. 

Saturated. Fully satisfied. Containing all possible. 

Slag. A nearly black glass formed in blast furnaces in the re- 
duction of iron and other metals. 

Sublimate. The substance obtained by sublimation. 

Sublimation. The process of vaporizing a solid which boils with- 
out melting, and collecting the vapors. 

Supernatant. Overlying. Said of a liquid above a precipitate 
which has settled. 

Ternary. Composed of three elements or more. 

Upward Displacement. Method of collecting light gases by let- 
ting them flow upward into a bottle of air, displacing the 
air. 

Volatile. A term applied to substances which readily change in- 
to gas. 

Volumetric. Estimation of quantity by measuring the volume, 
not weight. 



GLOSSARY 291 

Common or Commercial Names 

Agate. A species of quartz, often beautifully colored in con- 
centric rings. 

Alabaster. A beautiful white or delicately tinted form of gyp- 
sum. 

Alum. A double sulphate, containing a univalent and a triva- 
lent metal. Common alum is potassium aluminum sulphate. 

Alumina. Aluminum oxide. 

Amethyst. A variety of quartz, pale violet in color. 

Antichlor. A substance employed to neutralize the chlorine used 
in bleaching. It is generally sodium thiosulphate. 

Arsenic. The usual commercial name for arsenic trioxide. 

Arsenous Acid. A term often applied to arsenic trioxide. 
Strictly speaking arsenous acid is H AsO o . 

Arsine. Hydrogen arsenide also called arseniuretted hydrogen, 
H 3 As. 

Baryta. Barium oxide, BaO. 

Baryta Water. Barium hydroxide, Ba(HO) . 

Bauxite. Hvdrated aluminum oxide, Al O -H O. 

'232 

Benzene. More properly called benzol, C,jH 6 , obtained from 
coal tar. 

Benzine. A light oil resembling ordinary gasoline, obtained from 
petroleum. 

Bicarbonate of Soda. Cooking soda, XaHC0 3 . 

Bituminous. Containing bitumen or oil. 

Blanc de fard. Bismuth oxynitrate, BiOX0 3 . 

Blue Vitriol. Copper sulphate crystals. 

Borax. Sodium tetraborate. 

Butter of Antimony. Antimony chloride, so called from its yel- 
low color. 

Calcite. Crystallized calcium carbonate, being three in scale 
of hardness. 

Calomel. Mercurous chloride, Hg 2 Ci9. 

Carborundum. Silicon carbide, SiC, used as an abrasive. 

Caustic Potash. Potassium hydroxide. 

Caustic Soda. Sodium hydroxide. 

Chalcedony. A variety of quartz. 

Chalk. A soft, natural form of calcium carbonate. 

Chloride of Lime. Commercial name for bleaching powder. 

Chrome Alum. A double sulphate of potassium and chromium. 



292 CHEMISTRY FOR NURSES 

Chrome Yellow. Lead chromate, PbCrO . 

7 4 

Copperas. Ferrous sulphate*, green vitriol. 

Corrosive Sublimate. Mercuric chloride, HgCl 2 . 

Corundum. Native, uncrystallized aluminum oxide, nine in scale 

of hardness. 
Emerald. Aluminum oxide, crystallized, green in color. 
Emery. An impure, native form of aluminum oxide. 
Epsom Salts. Crystallized magnesium suliDhate. 
Felspar. A complicated silicate rock, which, decomposed, forms 

clay. 
Fool's Gold. Iron pyrites, FeS 2 . 
Fuller's Earth. A white variety of clay. 
Green Vitriol. Ferrous sulphate. 
Gypsum. Native calcium sulphate, CaSO -2H O. 

' 4 2 

Hartshorn. An old name for ammonia, so called because made 

from the horns of deer. 
Hypo. Sodium thiosulphate, used in photography as fixing bath 

and as an antichlor. 
Iceland Spar. A transparent, crystallized variety of calcium 

carbonate. 
Jeweler's Rouge. Ferric oxide, native, used in polishing and as 

a paint. 
Kelp. A variety of seaweed. Also applied to the ashes derived 

by burning the seaweed. 
Labarraque's Solution. Sodium hypochlorite, NaClO. 
Lac Sulphuris. A fine white precipitate of sulphur in limewater. 
Laughing Gas. Nitrous oxide N 2 0. 
Lime. Calcium oxide. 

Limestone. Native calcium carbonate, uncrystallized. 
Limewater. Calcium hydroxide solution. 
Lunar Caustic. Silver nitrate in stick form containing small 

percentage of silver chloride. 
Magnesia. Magnesium oxide. 
Marble. Crystallized limestone. 
Milk of Lime. Calcium hydroxide solution containing lime in 

suspension. 
Minium. Bed Lead, Pb 3 4 . 

Naphtha. A low boiling gasoline obtained from petroleum. 
Nitre. Potassium nitrate. 

Nordhausen's Acid. Fuming sulphuric, H2S9O7. 
Oil of Vitriol. Sulphuric acid. 



GLOSSARY 293 

Opal. A variety of silica. 

Paris Green. Copper aceto-arsenite. 

Pearl Ash. Pure potassium carbonate. 

Plaster of Paris. Monohydrated calcium sulphate, CaSO *H o O. 

Plastic Sulphur. Amorphous sulphur, prepared by pouring boil- 
ing sulphur into cold water. 

Potash. Commercial potassium carbonate. 

Powder of Algaroth. Impure antimony oxychloride. 

Purple of Cassius. A purplish colored compound obtained by add- 
ing to a solution of gold chloride a small amount of stannous 
and stannic chloride. 

Pyrites. Usually means iron pyrites, FeS 2 . There is also a copper 
pyrites. 

Quicklime. Lime. 

Red Precipitate. Mercuric Oxide. 

Sal Ammoniac. Ammonium chloride. 

Sal Soda. Crystallized sodium carbonate. 

Salt Cake. Sodium sulphate as obtained in the Leblanc proc- 
ess of making sal soda. 

Saltpeter. Potassium nitrate. 

Scheele's Green. Acid copper arsenite, CuHAs0 3 . 

Silica. Silicon dioxide. 

Slaked Lime. Calcium hydroxide, formed by adding water to 
lime. 

Smoky Quartz. A variety of quartz; silica, brown in color, some- 
times almost black. 

Soda. Usually cooking soda is meant. Sodium bicarbonate, 
NaHG0 3 . 

Subnitrate Bismuth. Bismuth oxynitrate, often sold as "bis- 
muth." BiOXO o . 

Sugar of Lead. Lead acetate, Pb(C o H o O o ) o *3H 7 0. 

Vermilion. Artificial mercuric sulphide. 

White Arsenic. Arsenic trioxide. 

White Lead. Basic lead carbonate; a common white pigment. 

White Vitriol. Crystallized zinc sulphate. ZiiS0 4 '7H 9 0. 

Zinc White. Zinc oxide, ZnO. A common white pigment. 



BIBLIOGRAPHY 

There will come times when every student will wish 
to pursue further some line of thought suggested by the 
text. The following books will be found valuable inas- 
much as they cover a wide range of practical subjects 
in chemistry; and with few exceptions they are not 
large works, are interestingly written, and not too 
technical. 

Air, Water, and Food, Richards and Woodman. John Wiley & 

Sons, New York. 
A Short History of Chemistry, V enable. D. C. Heath & Co., New 

York. 
Bacteria, Yeasts, and Molds, Conn. Ginn & Co., Boston. 
Chemical History of a Candle, Faraday. Harper & Bros., New 

York. 
Chemistry in Its Relation to Daily Life, KaMenberg and Hart. 

Macmillan Co., New York. 
Chemistry of Common Life, Johnston. D. Appleton & Co., New 

York. 
Chemistry of Everyday Life, Lassar-Cohn. J. B. Lippincott Co., 

Philadelphia. 
Chemistry of Food and Nutrition, Sherman. Macmillan Co., New 

York. 
Discovery of Oxygen, Priestley. Che'mical Publishing Co., Easton, 

Pa. 
Early History of Chlorine, Reprints. Chemical Publishing Co., 

Easton, Pa. 
Essays in Historical Chemistry, Thorpe. Macmillan Co., New York. 
Examination of the Urine, Saxe. W. B. Saunders Co., Philadelphia. 
Foods and Their Adulterants, Bruce. D. Van Nostrand Co., New 

York. 

Foods and Their Adulteration, Wiley. P. Blakiston's Son & Co., 
Philadelphia, Pa. 

294 



BIBLIOGRAPHY 295 

I'ood Preservatives, Eccles. D. Van Nostrand Co., New York. 
Oases of the Atmosphere, Ramsey. Macmillan Co., New York. 
Household Chemistry, Yulte and Goodell. Chemical Publishing Co., 

Easton, Pa. 
Household Physics, Lynde. 
Modern Bleaching Agents, Bottler. D. Van Nostrand Co., New 

York. 
Physiological Chemistry, Beeoe and Buxton, Macmillan Co., New 

York. 
Pure Foods, Olsen. Ginn & Co., Boston. 
Pure Water and How to Get It, Hazen. John Wiley & Sons, 

New York. 
Sanitary and Applied Chemistry, Bailey. Macmillan Co., New 

York. 
The Chemistry of Commerce, Duncan. Harper & Bros., New York. 
Toxicology, Diuiglit. Lea Bros. & Co., Philadelphia. 



IXDEX 



Acetylene, 172 

Acids, named how, 118 

organic, 161 

some familiar ones, 120 
After-damp, 159 
Air, a mixture, 18 

composition of, 17, 18 

fixed, 17 

inflammable, 17 

moisture in, 51 

need of fresh, 50 

phlogisticated, 47 
Alchemy, 18 
Alcohols, 159 

denatured, 160 

ethyl, 160 

methyl, 160 

wood, 160 
Aldehyde, formic, 163 
Alkali metals, 211 
Alkalies, 117 
Allotropic forms, 66, 67 
Alum, 211 

burnt, 211 
Aluminum, 239 

alloys of, 213 

hydroxide, 211 

preparation of, 210 

properties of, 211 

uses, 212 
Amethyst, 207 
Ammonia, 126 

characteristic, 127 

solubility, 127 

source of, 126 
Amylene, 170 
Anhydrides, 117 
Anode, 21 
Antimony, 202 

compounds of, 202 

poisoning by, 267 

tartrate, 202 

uses, 202 



Aqua regia, 88 
Arsenic, 198 

antidote, 199, 267 

characteristics, 198 

tests, 199 

trioxide, 199, 267 

uses, 198 
Atmosphere, 16 

early ideas of, 17 
Atomic theory, 101 

weights, 105 
Atoms, 101 
Avogadro's hypothesis, 10± 



Baking powders, 212 
classes of, 212 
healthfulness of, 213 
Balloons, 11 
Barium compounds, 228 
Barometer, 98 
Bases, 116 

named how, 118 
Bismuth, 202 

compounds, 203 

subnitrate, 203 

uses, 203 
Blue vitriol, 219 
Borax, 217 

Bordeaux mixture, 219 
Bovle, Bobert, 19 
Boyle 7 s Law, 96, 100 
Bread, aerated, 215 

yeast, 211 
Brimstone, 179 
Bromine poisoning, 266 
Butter, 166 
Butylene, 170 
Butyrin, 166 



C 



Calcium, 221 
chloride, 221 
group, 220 

light, 4:4: 



297 



.298 



INDEX 



Calcium — Cont 'd 

natural compounds, 221 

sulphate, 221 
Calomel, first use, 19 
Cantharides, 272 
Carbides, 154 
Carbon, allotropic forms, 142 

distribution, 142 

dioxide, 152 
uses, 152 
respiration, 49, 51 

monoxide, 149 
danger of, 151 
sources of, 149 

tetrachloride, 153 
Carbona, 154 
Carbohydrates, 173 
Carbolic acid, 271 
Carborundum, 154 
Catalysis, 58 
Cathode, 21 
Celluloid, 134 
Cements, 224 
Chalk, 221 

prepared, 223 
Charcoal, 145 

uses, 146 
Charles' Law, 93 

application of, 100 
•Chemical changes, 23 
Chemical union, 23 
•Chlorine, 80 

bleaching by, 84 

characteristics, 82 

liquid, 85 

manufacture of, 82 

preparation in laboratory, 81 

uses, .84 
Chloroform, 159 
Choke damp, 159 
•Chrome yellow, 256 
Coal, 148 

gas, 147 

tar, 147 
Cocoanut oil, 168 
Coke, 146 
Collodion, 134 
Compounds, 20 

named how, 20 

unsaturated, 138, 170 



Copper, characteristics of, 248 

deposits, 247 

group, 247 

poisoning, 269, 270 

sulphate, 248 

uses, 248 
Coquina rock, 221 
Corn sirup, 173 
Corrosive sublimate, 236 
Cottolene, 172 
Cottosuet, 172 
Crisco, 172 
Croton oil, 272 
Cryolite, 241 

D 

Decomposition, double, 24 

simple, 24 
Deliquescence, 31 
Detonators, 133 
Diamond, 142 

comparison, 143 

composition of, 143 

origin, 143 

uses, 144 
Drummond light, 44 

E 

Efflorescence, 33 
Electrodes, 20 
Electrolysis of salt, 75 

of water, 28 
Electrotyping, 249 
Elements, 20 

negative, 21 

positive, 21 
Emery, 240 
Equations, 112, 113 
Esters, 164 
Ethereal salts, 164 
Ethers, 164 
Ethylene, 170 



Fertilizers, nitrate, 54 

phosphates, 197 
Fiber silk, 134 
Fire damp, 158 
Fire extinguishers, 152 
Formaldehyde, 163 
Formalin, 163 



INDEX 



299 



Formulas, 109 

structural, 110, 111 
Fuller's earth, 240 
Furnace, electric, 144 
Fusible plugs, 203 

G 

Galvanized iron, 233 
Gas carbon, 147 
Gas laws, 98 

deductions from, 100 

masks, 84, 146 

natural, 148 
Gases, diffusion of, 49 

effects of pressure, 95 

pressure of, 103 
Gasoline, 159 
Geber, 18 
Giant powder, 132 
Glass, Bohemian. 208 

crown. 207, 208 

flint, 208 

tumblers. 209 

water, 207 
Glossary, 288 
Glucose, 173 
Glycerine, 165 
Glyceryl salts, 165 
Graphite, 145 
'Gun cotton, 133 

powder, 217 

H 
Hair dyes, 252 
Halogens, 80 
Hardness in water, 226 

cost of, 227 
Heat, effects of, 93 
Human body, Paracelsus ' idea, 
18 
temperature maintained, 
52, 60 
Humidity, 52 

and health, 52 
Hydrates, 31, 32 
Hydrocarbons, 158 

derivations of, 159 
Hydrochloric acid, 86 

uses, 87 
Hydrogen chloride, 86 
discovery, 38 



Hydrogen — Cont ? d 

occurrence, 39 

preparation, 39 

peroxide, 69 
test, 70 
uses, 70 

preparation from acids, 42 

preparation from oils, 44 

preparation from water, 28, 
41 

properties, 43 

uses, 43, 44 
Hydrogenation, 172 
Hydroxides, 117 
Hygroscopic substances, 31 
Hypo, 191 

I 

Iatro-chemists, 18 
lee manufacture, 128 
Iodine, 88 

characteristics, 89 

poisoning by, 266 

preparation, 89 

test, 90 

uses, 90 
Iodoform, 90, 159 
Iron, 258 

varieties, 259 
Isomeric bodies, 110 

K 

Kaolin, 240 
Karo, 173 
Kerosene, 159 
Kindling temperature, 62 
of paper, 63 

L 

Lakes, 245 
Lanolin, 218 
Lead, 254 

acetate, 256 

carbonate, 256 

characteristics of, 255 

colic, 269 

oxide, 256 

poisoning, 268, 269 

uses, 255 
Legumes, 54 
Lime, 221 

uses, 222 
Lunar caustic, 252 



300 



INDEX 



M 

Magnesium, 231 

oxide, 232 
Marsh gas, 158 
Marsh's test for arsenic, 200 
Matches, 196 

safety, 197 
Matter, Geber's theory, 18 

modern idea of, 19 

not continuous, 101, 102 

old ideas of, 15 

states of, 93 

transmutation, 15, 16, 17 
Mazola, 166 
Mercuric chloride, 236, 268 

fulminate, 237 

oxide, 237 
Mer cur ous chloride, 235 
Mercury, 235 

Metals, electromotive series, 40 
Methane, 158 
Microcrith, 105 
Mixtures, 22 
Molecular theory, 102 
Molecules, 102 

in motion, 103 

weights, 105 
Muriatic acid, 87 

N 
Neurotics, 273 
Neutralization, 120 
New skin, 134 
Nitric acid, 129 

characteristics, 131 
uses, 132 
Nitrogen family, 194, 204 
in human body, 54 
oxides, 130 
value in air, 53 
Nitrocellulose, 133 
Nitroglycerine, 132 
Nitrous oxide, 131 

O 
Oils, < ' cracking of, ' ' 149 

unsaturated, 171 
defines, 169 
Olein, 166, 171 
Oleomargarine, 166 

nut, 168 



Oxalic acid poisoning, 271 
Oxidation, 63 

spontaneous, 64 
Oxides, 115 

classes, 116 

reactions of, 116, 117 
Oxygen, 56 

characteristics, 60 

experiments, 59 

in respiration, 49 

preparation, 57, 59 

uses, 60, 61 
Oxyhydrogen blowpipe, 44 
Ozone, 66 

characteristics, 67 

preparation, 68 

uses, 68 

test, 68, 70 
Ozonizer, 68 



Palmitin, 166 
Paraffins, 158 
Paracelsus, 18 
Paris green, 201 
Peanut oil, 168 
Pearl ash, 218 
Periodic Law, 277 
Periodic Table, 279 
Petroleum, 149 
Phenol poisoning, 271 
Phosphates, 197 
Phosphorus, 194 

forms of, 195 

poisoning by, 265 

uses, 196 
Phossy jaw, 196. 
Photographic papers, 252 
Picric acid, 134 
Pineapple, artificial, 165 
Plaster of Paris, 223 
Poisons, 261 

classes of, 262 

susceptibility to, 263 

table of, 275 
Poisoning by alkalies, 264 

by strong acids, 263 
Potassium carbonate, 218 

chlorate, 218 

hydroxide, 218 

nitrate, 217 



INDEX 



301 



Propylene, 170 
Ptomaines, 272 
Pyrene, 154 



Quartz, 207 



Q 



E 



Eadicals, 111 
Reactions, addition, 24 
Reasoning, methods of, 17 
Refrigeration, 128 
Reinsch's test, 199 
Ruby, 240 



Salt, common, 73 

composition of, 75 

electrolysis of, 75 

impurities in, 74 

uses, 75 
Salts, 120 

acid, 121 

basic, 121 

binary, 123 

named how, 122 

neutral, 121 
Saponification, 168 
Sapphires, 240 
Settling basins, 35 
Silica, 206 
Silver, 250 

nitrate, 251 

uses, 251 
Smokeless powder, 134 
Soap, 168 

cleansing by, 169 

kinds of, 216 

soft, 169 
Sodium, 76 

acid carbonate, 211 

bicarbonate, 211 

carbonate, 215 

hydroxide, 216 

properties of, 77 

thiosulphate, 191 

uses, 78 
Starch, 173, 174 
Stearin, 166, 171 
Steel, 259 

tempering, 260 



Strontium compounds, 228 
Sugar, cane, 173, 174 

milk, 174 
Suint, 218 
Sulphides, 182 
Sulphur, 178 

acids of, 186 

crystals, 180 

dioxide, 185, 186 

flowers, 179 

plastic, 180 

properties, 181 

uses, 181 
Sulphuric acid, 187 

dehydrating agent, 132 
ether, 164 
fuming, 189 
uses, 191 
Sulphurous acid, 184 
Symbols, 109 

origin of, 108 

T 

Tables : 

atomic weights, 291 

bibliography, 294 

chemical formulas, 284 

chemical names, 284 

chemical terms, 288 

commercial names, 291 

elements, 283 

measures, 282 

periodic, 279 

poisons, 275 

temperatures, 281 

thermometer equivalents, 282 

weights, 282 
Tar, 187 

Tartar emetic, 202 
Temperature corrections, 99 

standard, 95 
Thermit, 242 
Thermometer, absolute, 94 

comparison, 94 
Tin, 254 

characteristics, 255 

uses, 255 
T. N. T., 134 

V 

Valence, 136 
degrees of, 140 



302 



INDEX 



Valence — Cont 'd 

in ternary compounds, 139 

variation, 139 
Ventilation, 50 
Vermilion, 237 
Vinegar eels, 162 

mother of, 262 
Vulcanite, 182 

W 

Washing powders, 215 
Water, composition of, 28, 29 

electrolysis of, 28 

forms of, 26 

glass, 207 

in foods, 26, 27 

purification of, 31, 34, 69 



Water— Cont 'd 
of combination, 31 
of crystallization, 31 
solvent powers, 33 
synthesis of, 29, 30 
tests for, 36 
treatment for algae, 35 

White lead, 256 



Zero, absolute, 94 

Zinc, 232 

compounds, 234 
poisoning, 270 
properties, 233 
uses, 233 



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